Chemical Wood Surface Improvements: Comparison
View Latest Version
Please note this is a comparison between Version 2 by Jason Zhu and Version 1 by Simon Pepin.

Increasing the use of wood in buildings is regarded by many as a key solution to tackle climate change. For this reason, a lot of research is carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as increased durability, fire-retardancy, superhydrophobicity, and self-healing.

  • wood
  • Surface Improvements
  • Modifications
  • Coatings

1. Coatings

Coatings were the most intensively studied methods for the protection of wood surfaces during the last five years. A total of 144 papers were found on this subject, using diverse materials and application methods to improve surface properties, such as hydrophobicity, hardness, abrasion resistance, photostability, thermal stability, self-healing, self-cleaning and more.

1.1. Organic Coatings

Organic coatings are very common in wood protection, including waxes, oils, and film-forming resins such as acrylics, alkyds and polyurethanes. While they can be improved with additives, a popular approach found in the latest literature to enhance the properties of film-forming organic coatings was to use strategic reactives to change key properties of the resin itself. Different fire-retardant coatings were reported using phosphorus containing monomers or reactive diluents [30,31,32,33][1][2][3][4]. Lokhande et al. used glycidyl methacrylate, piperazine, and cyclic ethylene chlorophosphite to develop a diacrylate reactive diluent yielding UV-cured coatings with increased thermal resistance, hardness, hydrophobicity and stain resistance [34][5]. They found that the thermal properties of the coating would improve with the content of their reactive diluent, a concentration of 25% increasing the weight-loss temperatures, the heat-index resistance (from 149.7 °C to 184.0 °C), the practical char yield at 600 °C (7.12% to 22.21%), and the limiting-oxygen index (23% to 33%) when compared to the same coating without the reactive diluent. A similar coating was developed by Mulge et al. using epoxy acrylate oligomers and phenylphosphonic dichloride [35][6]. However, it was found that while a higher P content would improve the thermal stability of the coating, it would eventually impair its physical properties. In a similar way, Paquet et al. created self-healing, film-forming coatings by using acrylic monomers and oligomers containing many hydroxyl groups [36][7]. By using 2-hydroxyethyl methacrylate and an aliphatic urethane acrylate oligomer (Ebecryl 4738), the obtained polymer that could completely heal a 5 μm deep scratch or regain 83% of the gloss lost to abrasion after being heated to 80 °C for two hours. Another use for this practice was to build fast UV-curing acylic [37][8] and polyurethane-acrylate [38][9] formulations.
The same strategy was used to prepare more environmentally friendly coatings by using bio-based materials as a reactive. Raychura et al. prepared polyurethane coatings by reacting diisocyanates with fatty amides of mahua [39][10] and peanut [40][11] oils. The obtained wood coatings scored 100% on a cross-cut adhesion test, 1H or 2H on pencil hardness tests, and had a good stability to weak acids, water and NaCl solutions. Interestingly, wood coatings with good resistance to termites and/or white rot fungi could be obtained by reacting the starch from a yam (Dioscorea hispida sp.) with polyvinyl alcohol [41][12] or polyacrylamide [42][13]. Another antiseptic coating was prepared by Dixit et al. with citric acid and glycidyl methacrylate [43][14], which had high adhesion (5B), pencil hardness (6H), solvent resistance and a 15 mm zone of inhibition against the bacteria Staphylococcus aureus. It will be shown later in the review that cellulose nanocrystals (CNCs) were extensively studied as additives for organic coatings; Kong et al. [44][15], however, innovated by using CNCs as a reactive to imbue a waterborne polyurethane coating with a higher hardness and resistance to abrasion. They found that using only 0.1% of CNCs modified with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in their coating would increase its tensile strength and tensile elongation by 59% and 55%, respectively. More bio-based chemicals were studied by other workers, including soybean oil [45][16], rapeseed oil [46][17], and biosourced alcohols and acids [47][18].
Some organic coatings were prepared using very distinctive methods and could not be categorized into a specific trend, but still deserve some attention [48,49,50][19][20][21]. Janesch et al. dip-coated spruce in tung oil, bee wax, or a mix of both, before sifting sodium chloride (NaCl) on the freshly coated wood [51][22]. The NaCl, which created a micro-/nanoscale architecture into the coating, was removed one week later by rinsing with distilled water. The resulting wood surface was 100% natural, food safe and had a contact angle with water of 161°, but was not considered superhydrophobic as its roll-off angle was extremely high. Zhang et al. designed a biogel coating based on chitosan, gelatin and glycerol that had quite a low adhesion (1.4 MPa), but some very interesting features [52][23]. It could completely heal medium damages under heating, be reused after being scrapped from the wood and dissolved in water, and be colored with water-soluble dyes. A 3-layers coating was produced on beech wood with a polydopamine primer, an hydroxyapatite second layer, and a chitosan topcoat made from shrimp wastes [53][24]. The composite coating showed good hydrophobicity (contact angle = 130°), photostability and resistance to seawater. After 6 months of immersion in the sea, the treated samples showed lower chemical degradation, color changes (E* = 12.68 vs. 22.24) and damages from barnacles than the controls samples. Liu and Hu prepared polystyrene colloidal microspheres with different acrylate-based copolymers [54][25]. Once casted on aspen, the very densely arranged microsphere exhibited different colors, such as green, orange and red. Other unique organic coatings were developed by using materials, such as chitosan oligomers, vegetable oil, castor oil and lignin to protect wood from decay fungi [55][26], fire [56][27], and photodegradation [57,58][28][29].

1.2. Additives in Organic Coatings

While it was shown in the previous section that organic wood coatings could be improved by using the appropriate reactives, another great way to obtain performant coatings is through the inclusion of functional additives. Organic, bio-based materials have been the subject of much research over the last 5 years. They are very interesting substances for wood protection, as they biodegrade upon leaching. Cellulose nanocrystals and nanofibrils received a lot of attention due to their potential to improve the mechanical properties of the softer oil- or resin-based organic coatings [59,60,61,62,63][30][31][32][33][34]. Tian et al. prepared a renewable UV-cured polyester methacrylate coating based on L-lactide and ε-caprolactone, containing 0% to 7.5% of cellulose nanocrystals (CNCs) [64][35]. The properties of the resulting composite coating changed proportionally to the concentration of CNCs, with an increase in bending strength, bending modulus, hardness and water contact angle, but a decreased tensile strength and elongation at break. At a 7.5% content of CNCs, the coating had a grade 3 adhesion, a 5H pencil hardness and a 103° contact angle. Veigel et al. incorporated 1% of cellulose nanofribrils (CNFs) to linseed oil after modification with acetic anhydride and (2-dodecen-1-yl)succinic anhydride to increase their solubility [65][36]. While the beech substrate coated with this varnish had the same initial hydrophobicity as the samples treated without the CNFs, the reduction of the hydrophobicity caused by multiple cycles of abrasion with a Taber Abraser was much slower for the CNFs containing formulations, showing a greatly reduced loss of oil. Kaboorani et al. modified cellulose nanocrystals (CNCs) with hexadecyltrimethylammonium bromide to improve their compatibility with a UV-cured acrylic resin [66,67,68][37][38][39]. They found that a loading of 3% of CNCs significantly enhanced the pencil hardness, tensile strength, modulus of elasticity, and thermal stability of the coating, while reducing its mass loss following abrasion and water vapor uptake and transmission rate. Cheng et al. found that adding CNCs and silver nanoparticles to a polyurethane coating exhibited a synergistic effect toward the antimicrobial properties of the coating, while also improving its adhesion [69][40]. Tree extracts were another type of additives that received a lot of attention, this time to imbue wood with better photostability [70,71][41][42]. Acrylic coatings containing condensed tannins and modified tannins were prepared by Grigsby to protect radiata pine [72][43] before exposition to natural and accelerated weathering. A loading of less than 0.5% of tannins was sufficient to extend the coating’s life up to 20% more than commercially available hindered amine light stabilizers (HALS) and phenolic stabilizers could. Tomak et al. coated Scots pine with water-based acrylics containing tannins from different woods species in the presence [73][44] or absence [74][45] of metallic oxides. They found that after 1512 h of artificial weathering, their coatings could outperform the commercial reference coating in terms of color changes and chemical degradation. It appeared that the lower concentrations of extractives were more effective against UV degradation, and that the interactions between the different tannin and oxides types were completely random. Waterborne acrylic containing CNF and bark extractives was prepared by Huang et al., which yielded both photostability and better mechanical properties (hardness and abrasion resistance) [75][46]. Finally, Yan et al. prepared acrylic wood coatings containing delignified wheat-straw powder, either raw or after calcination [76][47]. The resulting coatings showed good resistance to molds, especially when the wheat straw was calcined.
Some non-bio-based, organic wood coating additives were also studied over the last five years, sometimes under the form of microcapsules. Zhu et al. prepared urea-formaldehyde microcapsules loaded with thermochromic material to make color-shifting wood under thermal stimuli [77][48]. A waterborne varnish containing 20% of the microcapsules showed an important color change toward the red and yellow, according to the CIELAB analysis, when heated between 31 °C and 37 °C. The color change was then perfectly reversible between 34 °C and 26 °C. Other workers studied the development of heat sensitive wood, either with microcapsules [78][49] or not [79,80][50][51]. A self-healing acrylic coating was prepared by Yan and Peng by encapsulating resin in urea-formaldehyde microcapsules [81][52]. They found that a loading of 4% of microcapsules was enough to imbue the coating with good self-healing capacities without affecting its mechanical properties. Similarly, Queant et al. encapsulated organic UV absorbers in calcium carbonate microspheres in order to protect them from degradation [82][53]. A 2500 h accelerated weathering test showed that wood coated with a transparent waterborne latex would suffer less color changes when the UV absorbers were encapsulated. Other uses for organic additives in wood coatings during the last five years included the enhancement of their mechanical properties [83][54] and the reduction of the oxygen inhibition [84][55].
Nanoparticles of metal oxides and silica as wood coating additives allow the preparation of surfaces with a wide array of functionalities. An interesting method to achieve superhydrophobicity was to modify the nanoparticles with a low surface free energy chemical before their incorporation into the coating [85,86,87,88][56][57][58][59]. The low surface free energy of both the modified nanoparticles and the resin would imbue water repellency, and the nanoparticles brought an appropriate micro-/nanoscale architecture to the coating, joining together the two requirements to achieve superhydrophobicity. Sevda et al. experimented the addition of SbO3 and TiO2 to an intumescent paint [89][60]. They noted that a loading of 2% of nanoparticles increased of LOI and greatly decreased the weight loss and smoke generation in comparison to the paint alone. Guo et al. prepared bio-sourced silica particles through the calcination of rice husk [90][61]. After modification with a silane coupling agent (KH-570), a 2% loading of the silica in a waterborne acrylic coating improved the elongation at break (244.72% to 303.06%), tensile strength (32.509 MPa to 48.673 MPa), modulus of elasticity (3.010 MPa to 6.672 MPa), and pencil hardness (1H to 2H) of the resulting coating. Other workers explored the possibilities of these compounds to improve the resistance of wood to decay fungi [91[62][63],92], black-stain fungi [93][64], and photodegradation [94][65], as well as to improve its mechanical properties [95,96][66][67].
In addition to metallic oxides and silica, inorganic compounds of mineral origin were used as additives to improve the properties of organic wood coatings. Atienza et al. used oyster shell powder to make a thermally stable acrylic coating [97][68]. Because the shells are made of 95%–98% of incombustible calcium carbonate, the addition of 75% of oyster shell powder to the coating increased the time of burning of the wood samples from 18.00 min to 29.67 min. Zeolites were also considered as potential fire retardants in a melamine-urea-formaldehyde resin containing ammonium polyphosphate [98][69]. Due to their very porous nature, most of the zeolites studied showed an appreciable decrease in CO2 production. The ignition time was also greatly delayed, from 138 s for the resin containing only ammonium polyphosphate to 279 s with 3A zeolites. Although different zeolites performed the best on the different aspects of fire protection, 3A zeolites were, overall, the most performant. Other compounds studied as fire retardants were graphene [99][70] and sepiolites [100][71], which could also be used to make hydrophobic coatings. Kolya and Kang coated various species of hardwood with polyvinyl acetate coatings containing modified graphene oxide [101][72]. The graphene oxide, which had been reduced with NaBH4 in presence of urotropin and further functionalized with poly (diallyl dimethylammonium chloride), slightly increased the water contact angle of the coating on most wood species, with average angles of 91.5° and 92.7° on the radial and cross-sectional face, respectively, as compared to 72.5° and 80.1° for the polyvinyl acetate coating alone. Similarly, Chen et al. functionalized sepiolite with polysiloxane and mixed them with an epoxy [102][73]. They found that the hydrophobicity of the coating increased rapidly with higher sepiolite:epoxy ratios, with highly superhydrophobic (water contact angle = 166° and roll-off angle = 5°) at 7:5. The wood surface also exhibited good self-cleaning properties and the ability to separate water and oil.

1.3. Organic-Inorganic Composite Coatings

An extremely large share of the research into wood coatings, over the last five years, focused on the organic-inorganic composite coatings. This section differs from the additives in organic coatings for a few reasons: 1- the organic and inorganic parts, in this section, are not always blended together, 2- the organic part is often not a resin, and 3- the inorganic part is frequently the main component of the coating. Also, organosilicons are an important element of these coatings.
A method frequently encountered to improve the hydrophobicity of the wood surface, and often reach superhydrophobicity, was to use nanoparticles to form a proper micro-/nanoscale architecture and thereafter reduce its surface free energy. For this matter, an organic coating could be used to reach the desired low surface free energy [103,104][74][75]. A superhydrophobic wood surface was prepared by Lozhechnikova et al. after applying positively charged ZnO nanoparticles and a negatively charged carnauba wax on Norway spruce through layer-by-layer deposition [105][76]. Not only did the coating reach a 155° water contact angle (WCA), but it also displayed higher UV stability and moisture buffering. Lu et al. pretreated rubberwood with IPBC, an organic biocide, before dipping it in polystyrene and SiO2 solutions [106][77]. At higher SiO2 concentrations (2%), the WCA was 155.6° and the antiseptic performances of the IPBC were preserved by the coating, which reduced its leaching. A superhydrophobic coating with a high thermal energy storage capacity was designed by Kong et al. through spraying with mesoporous polydivinylbenzene nanotubes, fluorine-containing SiO2 nanoparticles and paraffin wax [107][78]. Upon exposition to excessive heat, the wax trapped in the nanotube would melt to store thermal energy and later release this energy through crystallization. This kind of wood surface improvement strategy was also used by other workers to imbue wood photostability [108][79], molds resistance [109][80], self-healing [110][81], thermal stability [111][82], and improved adhesion of UV-curing coatings [112][83].
The hydrophobization of the micro-/nanoscale architecture could also be achieved by replacing the resins with low surface free energy components [113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103]. As a general rule, these coatings showed superhydrophobicity (contact angle > 150°, roll-off angle < 10°), high resistance to mechanical wear (abrasion, cutting, etc.), and sometimes properties such as chemical resistance and self-healing. Wang et al. developed an interesting method to grant superhydrophobicity to Chinese fir, where they obtained the desired micro-/nanoscale architecture simply by sanding the wood surfaces with a 240-grit sandpaper [133][104]. The surface free energy of the produced micro/nanoscale architecture was subsequently reduced by deposition of a fluoroalkylsilane/silica composite suspension to obtain a superhydrophobic surface with good abrasion resistance and self-healing capabilities. Guo et al. created a Mg-Al-layered double-hydroxide coating to improve the fire safety of birch wood via thermal deposition followed by hydrophobization with trimethoxy(1H,1H,2H,2H)heptadecafluorodecyl)silane [134][105]. The limiting oxygen index (LOI) of the coated wood increased from 18.9% to 39.1%, and its total smoke generation and total heat release decreased by 58% and 40%, respectively. Wang et al. coated poplar wood by dipping in polydopamine for 24 h, electroless Cu deposition for 12 h, and dipping in octadecylamine for 24 h [135][106]. Although the process was quite tedious, the resulting coating was extremely durable, keeping its superhydrophobicity even after degradation by UV light, acids, bases, organic solvents (n-hexane, acetone, ethanol, and DMF), and boiling water. Huang et al. modified nanofibrillated cellulose [136][107] and lignin-coated cellulose nanocrystals [137,138][108][109] coated wood with 1H,1H,2H,2H-perfluorooctyltrichlorosilane through chemical vapor deposition. The resulting wood surface showed high sandpaper abrasion and UV resistance, as well as superhydrophobic and self-cleaning behaviors. The naturally hydrophobic micro/nanoscale structure of canna leaves [139][110] and rose petals [140][111] was re-created by Yang et al. through nanoimprint lithography. They first created a PDMS template of the canna leaves and rose petals, which was use to make a perfect copy of the said structure with SiO2 and polyvinyl butyral. The copy could then be peeled from the template and stuck to the wood surface to reach superhydrophobicity. A similar strategy was used by Chen et al. to create superhydrophobic and magnetic wood surfaces based on the structure of taro leaves with F3O4 and PDMS [141][112]. Gan et al. also prepared superhydrophobic wood surfaces with a ferromagnetic behavior by dipping poplar samples in a solution of hydrophobized CoFe2O4 nanoparticles, which had a contact angle of 158°, high resistance to sandpaper abrasion, and improved microwave absorption properties [142][113].
Some organic-inorganic composite coatings were prepared simply by adding organic and inorganic moieties together on the wood surface. Wang et al. used tannic acid-Fe3+ complexes in combination with silver nanoparticles to create a superhydrophobic coating [143][114]. The developed coating was highly durable, keeping a contact angle higher than 150° after UV exposition and degradation by HCl, NaOH, n-hexane, acetone, ethanol, DMF and boiling water. A magnetic wood coating based on chitosan, sodium phytate and nano-Fe3O4 was prepared by Tang and Fu through layer-by-layer deposition [144][115]. They found that paramagnetic wood with narrow and long magnetic hysteresis loops could be created with this method, the magnetic properties of the treated wood being directly related to the number of layers in the coating. Uddin et al. prepared a paste with Mg(OH)2 and casein to improve Scots pine’s resistance to fire [145][116]. The prepared wood surface had a delayed time to ignition (12.1 s to 30.4 s), a lower peak heat release (216 kW/m2 to 119 kW/m2) and a lower total heat release (79.5 MJ/m2 to 53.3 MJ/m2), as well as decreased smoke production and mass loss. Another fire-retardant coating was prepared by Xie et al. through dipping in different solutions containing graphene oxide and functional cellulose [146][117]. These coatings scored a V-0 rating in a vertical burning test, FH-1 or FH-2 rating in a horizontal burning test, had a greatly increased LOI, and could self-extinguish when removed from the flame source. In presence of moisture, they could even self-heal incisions with widths up to 320 μm.

1.4. Inorganic Coatings

Metallic oxides and silica played an important role in the last five years of research in the domain of wood coatings [147,148,149][118][119][120]. They were layered on wood surfaces with a variety of methods, including sol-gels [150,151,152][121][122][123]. Sol-gels with SiO2, TiO2, and Fe3+ [153][124] or Zr4+ [154][125] were used to make photostable wood surfaces with photocatalytic activity, granting them self-cleaning capabilities through the photodecomposition of organic pollutants. Qian et al. also used sol-gels to develop a coating based on microcapsules with a Fe3O4/SiO2 shell and a phase changing material core to imbue energy storage and magnetism to poplar wood [155][126]. The hydrothermal growth and deposition of metallic oxides were also the subject of many publications [156,157,158,159][127][128][129][130]. Sun and Song casted WO3 on poplar wood through hydrothermal in situ synthesis [160][131] or nanosheet deposition [161][132] to build photochromic wood. The resulting wood surfaces could reversibly change color after exposition to UV radiations, had better photostability and could be hydrophobized with 1H,1H,2H,2H-heptadecafluorodecyl)silane. Similarly, MoO3 was hydrothermally grown or deposited on birch to yield photo-responsive wood with a blue shift when exposed to UV light [162,163][133][134]. Wang et al. prepared magnetic wood with fire-retardancy through the hydrothermal deposition of MnFe2O4 [164][135]. The initial burning time of the coated wood was delayed from 6 s to 20 s, its electromagnetic waves absorption capacity was improved, and it could additionally be hydrophobized with fluoroalkylsilanes [165][136]. A very interesting silica coating was prepared by Belykh et al. by mixing sodium liquid glass and black shale, which are byproducts from the fabrication of ferrosilicon and gold mining activities, respectively [166][137]. They found that good adhesion could be achieved by using 20%–35% of black shale, while 10%–25% yielded a good reduction of the mass loss when exposed to fire. They also found that adding 1% of a synthetic foaming agent (PO-6) improved both the adhesion and fire resistance of the coating.
Among the other approaches to coat wood with inorganic materials, Pan et al. used an electroless plating method to coat poplar disks with nickel (Ni) [167][138]. They found that the disks’ resistance would decrease from 12 Ω to 1 Ω within the first 5 minutes of electroless plating, that the hydrophobicity of the coated wood slightly increased, and that an electromagnetic shielding effectiveness between 55 Db and 65 Db could be achieved. Similar methods were also studied to coat poplar with Cu-Ni [168][139] and Ni-P [169][140] composites. A superhydrophobic wood surface was created by Wang et al. by deposing copper on a wood substrate with a vacuum evaporator, followed by the growth of a silver layer through immersion in a AgNO3 solution [170][141]. The prepared wood surface, which had a contact angle of 160.5° and a roll-off angle near 0°, could keep its superhydrophobicity after 100 cycles of tape abrasion or 200 cm of sandpaper abrasion with a 50 g weight. Hydrophobic wood surfaces were prepared by Łukawski et al. via drop casting and dipping with different solutions of carbon black, graphene, and carbon nanotubes [171][142]. Concentrations as low as 0.05 g/m2 of nanomaterials were sufficient to reach very high water contact angles (up to 143°), although superhydrophobicity was not achieved. They also found that, while carbon nanomaterials do not make covalent bounds with wood, the coatings’ resistance to sandpaper was quite good. Yuan et al. used hydrothermal deposition of graphitic carbon nitride nanosheets to improve the photostability of poplar wood [172][143]. They found that the nanosheets could absorb 90% of the UVA and UVB, substantially reducing the color changes after accelerated weathering. Furthermore, TG and DTG showed an improvement of the thermal stability of the coated wood. Another use of inorganic nanosheets as wood coatings was explored by Liu et al. who coated cedar wood with boron nitride nanosheet to improve its performance against fire [173][144]. The obtained wood surface showed a good thermal stability after 60 s of exposition to a lighter and an improved resistance to oxidation.

2. Wood Surface Modification

Instead of improving wood surfaces through the addition of an outer layer, different modification methods allow for the enhancement of the wood’s properties directly. These methods involve the chemical modification of the wood surfaces by different means to improve their wettability, decay-fungi resistance, photostability, and more.

2.1. Plasma Modification

An environmentally-friendly way to modify the surface of wood is through plasma treatments. Plasmas are highly reactive chemical environments with interesting features such as scalability and the absence of solvents [174][145]. They exist under various forms, which can be thermal or non-thermal [175][146]. In the case of wood protection, however, non-thermal plasmas are preferred to avoid its thermal degradation. An interesting use of plasmas in wood surface modification is to oxidize its polymeric constituents to increase its surface free energy and wettability. Over the last 5 years, many workers explored this application to increase the interactions between wood and adhesives or coatings [176,177,178,179,180,181,182,183,184,185,186,187][147][148][149][150][151][152][153][154][155][156][157][158]. They found that using reactive carrier gases such as air and O2 would lead to the creation of polar groups such as carboxyl and carbonyl at the surface of the treated wood, increasing its hydrophilicity and surface free energy. The plasma-treated wood would therefore have much lower contact angles with water and water-based coating solutions, showing an enhanced wettability, as well as a faster and deeper absorption of those liquids. As a result, the adhesion of coatings and adhesives would often be greater on treated wood than on its untreated counterpart.
Žigon et al. [188][159] and Žigonand Dahle [189][160] used a floating electrode dielectric barrier discharge (FE-DBD) plasma to treat Norway spruce following a short dip in NaCl solutions. They found that the electric conductivity and the intensity of the discharge were both increased by the NaCl, which led to an enhanced wetting of the wood following the plasma treatment. As a result, the contact angle with water and a water-based coating were lower and the tensile strength of the coating was improved. In another study, Žigon et al. used different adhesives to bind beech to aluminum and steel after treating both the wood and metals with a FE-DBD plasma [180][151]. The surface free energy of all the substrates increased following the plasma treatment, which led to higher tensile shear strength in most of the studied scenarios. After noting the poor adhesion of a water-based primer to beech veneers and of a water-based topcoat to an oily UV-cured primer, Peng and Zhang treated both the wood veneers and the UV-cured primer with a DBD plasma before laying the subsequent coat [190][161]. They found that the wettability of the beech veneers and the primer increased following the plasma treatment, which led to a large enhancement of their adhesion. Similarly, Dahle et al. dip-coated pine samples with polystyrene microspheres before proceeding to plasma modification of the coating [191][162]. As hydroxyl and carbonyl groups were created on the polystyrene layer, the wood surface became superhydrophilic and may eventually be used as a primer for further plasma polymerization. In an effort to improve the fireproofing of wood, Gospodinova and Dineff studied the effect of a plasma treatment on the absorption of fire-retardant solutions [192][163]. They found a substantial increase in the surface free energy and of the penetration-spreading parameter after the plasma treatment, but also a rapid decrease in these two variables during a post-treatment storage. Finally, Volokitin et al. used a thermal plasma treatment to mimic a thermal treatment on the surface of pine and birch [193][164]. Similar to typical thermal treatments, the modified samples were darker, their water contact angle increased, and their water absorption declined.
Other uses for plasma treatments in wood-surface protection are the grafting of chemical components and the creation of thin coatings. Due to their highly energetic and reactive nature, plasmas can melt metallic particles or break down organic molecules into reactive moieties while creating radicals on the surface of wood, which allows the growth of thin coating layers or the functionalization of wood surfaces [194,195][165][166]. Thereby, a Zn/ZnO thin coating was deposited on beech wood by Wallenhorst et al. through the cold plasma spraying of Zn microparticles with air as the process gas [195][166]. After 50 h of exposition to UV radiations, the thickest coating almost completely inhibited to color changes (E* ≈ 0), while uncoated wood had a E* of 10. They also found that the coating could protect a polyurethane topcoat from photodegradation. Similarly, Profili et al. prepared a hydrophobic ZnO/SiO2 composite coating on sugar maple with a DBD plasma [196][167]. The coating, formed by the embedding of ZnO particles in a SiO2 layer, displayed a static water contact angle of 100°, while the untreated samples quickly absorbed the water droplets. A superamphiphobic coating was casted on birch wood by Tuominen et al. by depositing titanium nanoparticles with a liquid flame spray followed by the plasma polymerization of perfluorohexane [197][168]. The coating, which displayed contact angles > 160° with water, ethylene glycol, diiodomethane, and olive oil, was also highly resistant as its wetting properties were still intact after a 500,000 water drops impact test. Furthermore, good self-cleaning properties were noted with both water and oil.
The hydrophobization of wood surfaces through plasma treatments with fluoroalkanes and organosilicons also received some attention over the last five years. Notably, de Cademartori et al. created a fluorocarbon film on white spruce and Brazilian cedar by polymerizing octofluoropropane with a DBD plasma [198][169]. They found that longer treatment periods would lead to higher hydrophobicity, with optimal water contact angles of 135.2° and 129.8° on the spruce and cedar, respectively. Levasseur et al. also used C3F8 to improve the hydrophobicity of sugar maple wood by DBD plasma with inert gases (Ar and N2) [199][170]. They noted that the hydrophobicity of the obtained surfaces was directly linked to the voltage of the plasma, which could yield a 140° static water contact angle at the highest voltage (10 kV). After letting the coating age for 125 days under uncontrolled conditions, the wetting properties of the wood surface remained unchanged. The possibility to increase or decrease the wettability of wood through cold remote (N2 +O2) plasma was studied by Bigan and Mutel [200][171]. They noted that the water absorption of different plasma-treated wood species could significantly increase (up to 5.5 timesin the case of beech) by using the plasma treatment alone, but that adding 1,1,3,3-tetramethyldisiloxane could make the wood superhydrophobic. Wood coatings with both hydrophobicity and good thermal stability were prepared by Sohbatzadeh et al. [201][172] and Chen et al. [194,202][165][173] through the plasma polymerization of hexamethyldisiloxane. Wood surfaces with lower surface free energy and increased roughness were obtained, yielding water contact angles as high as 138°. Many other studies were conducted over the last five years to improve the properties of wood surface through plasma treatments, including polyester powder [203][174], polyester with aluminium coated silver and bismuth oxide [204][175] or TiO2 [205][176], copper and aluminium microparticles with an acrylic binder [206][177], ZnO [207][178], TiO2 [208][179], and various biocidal precursors [209][180].

2.2. Other Surface Modification Methods

Beside plasma treatments, many methods were used, over the last years, to improve the properties of wood surfaces through modification. Herein, those methods are classified into two categories: chemical methods and carbonization methods. The chemical methods relied on chemical reactions or interactions to tone the properties of the outmost surface of the treated wood; a slight penetration of the chemicals into the wood was considered a surface impregnation, which will be reviewed in the next section. The chemical grafting of chemicals on the surface of wood involves the creation of a covalent bond between the wood cell wall and the modifying agent. This method allows to improve the surface properties of wood while reducing the leaching of the chemicals [210][181]. Wang et al. grafted poly(2- (perfluorooctyl)ethyl methacrylate) on the surface of Chinese fir by atom transfer radical polymerization [211][182]. The modified wood had a strong superhydrophobic behavior, which was only slightly affected by finger-wiping and tape-adhesion abrasion tests. Furthermore, the treated wood showed excellent resistance to the mold Aspergillus niger and self-cleaning properties. A similar method was used by Sharma et al. to graft acetonitrile and ethyl acrylate on pine wood [212][183]. Under optimal conditions, they obtained a percentage grafting of 85.34%, which greatly reduced the swelling of the treated wood in different solvents and solutions, as well as its weight loss when dipped in strong bases and acids. An environmentally-friendly treated was developed by Filgueira et al. as they grafted modified Pinus radiata tannins and condensed tannins on beech wood through the action of a laccase enzyme [213][184]. They found that treating wood this way, under an alkaline medium (pH = 10), would reduce its water absorption over 72 h by 20% and reduce the leaching of the treatment by 76%. Song et al. modified the surface of balsa wood by dipping samples for 60 s in aqueous solutions containing 0.75% of different salts [214][185]. They found that the metal ions, particularly Zr4+, could attain a water contact angle up to 145° through the creation of a microstructure and crosslinking. However, the durability of such treatment seems rather low, as the contact angle dropped to 138° after 14 days ambient conditions. The fluorination of silver fir and Douglas fir with gaseous F2 was studied by Pouzet et al. [215,216][186][187]. They found that the treatment would substitute hydroxyl groups from the cell wall polymers for fluorine, reducing the surface free energy of the treated wood. As a result, the water contact angle increased up to 120°, the water absorption decreased drastically, and the treatment was still as hydrophobic two years later. However, while short treatment times had only a low effect on the integrity and color of the treated wood, treatments of 20 min led to a severe degradation of the tracheids and browning of the wood surfaces. In another study, they also noted that a torrefaction post-treatment would help to purge the HF produced by the reaction of F2 with wood and further slow down the ingress of water without causing any defluorination of the treated wood [217][188]. The combination of a laccase enzyme surface treatment and pressure impregnation of copper(II) sulfate pentahydrate was explored by Gabrič et al. [218][189]. They found that a laccase pre-treatment would make the cell walls of the wood swell, preventing its impregnation; however, using the laccase as a post-treatment would greatly reduce the leaching of the copper. Furthermore, the laccase treatment alone could reduce the mass loss due to the degradation by brown- and white-rot fungi by roughly a third. More chemicals were studied over the course of the last five years to modify the surface of wood, including aminoborates [219][190], methanol [220][191], cellulase [221,222][192][193], poly(methylhydrogen)siloxane [223][194], and chitosan [224][195].
As the name implies, the carbonization methods revolve around charring the surface of wood to modify its properties. The use of CO2 lasers with radiation doses up to 75 J/cm2 was studied in several publications, as well as its effect on the tensile strength of adhesives, the resistance to molds of the treated wood and its surface free energy [225,226,227][196][197][198]. The authors found that high radiation doses would increase the wood surface blackening, as a result of the carbonization, as well as its resistance to molds. However, they noted that the treatment was only effective against Aspergillus niger. Studies of the surface properties showed that the loss of hydroxyl groups reduced the surface free energy of the treated wood, which decreased the tensile strength of polyurethane and polyvinyl acetate adhesives. Other authors explored the carbonization of wood by pressing a single surface of the treated wood with a hot metal plate at different temperatures (220 °C to 400 °C) for different periods (30 s to 2 h) [228,229,230][199][200][201]. They observed highly modified moisture-related behaviors, with higher water contact angles, lower water absorption, and lower equilibrium moisture contents (EMC). As a result of the reduced EMC, the modulus of rupture of the charred wood was also slightly higher. A similar study was conducted by Akçay et al., wherein, pine and beech surfaces were carbonized with a blow torch to improve the wood’s resistance to white- and brown-rot fungi [231][202].

2.3. Wood Surface Impregnation

The properties of the wood surfaces can be improved with a shallow impregnation of chemicals. It can be achieved by different means, from brushing and very short dippings (few seconds) to longer dippings (few hours) and single face vacuum impregnation. Very few publications on the subject of impregnation presented details about the impregnation depth of the chemicals or their distribution into the wood; consequently, different parameters were taken into consideration to decide if a method would be considered as a surface impregnation: the use or not of pressure/vacuum, the duration of the treatment, the size of the samples, whether the samples were completely or partially covered by the treatment, and the weight gain. Petrič described surface impregnation as the impregnation of the first few millimeters of the cross-section of wood [175][146]. While this definition was used as the basis to classify the treatments as surface impregnation, it seemed rather ambiguous, as some hard-to-treat species can only be treated by a few millimeters in the cross-section, even with a vacuum/pressure process. Accordingly, treatments that would allow high longitudinal penetration were also rejected.
A primary way to treat wood by surface impregnation was through the insertion reactive material. Triquet et al. chemically increased the surface density of various hardwood species by in situ polymerization of acrylate monomers [232][203]. The monomers were vacuum impregnated for 150 s after being dropped on a single surface of wood, which was followed by electron-beam polymerization. The density of the treated wood increased by nearly 200 kg/m3 near the surface, which lead to an augmentation of the Brinell hardness. Different workers studied the possibility of reducing the set-recovery of unilaterally compressed wood with the impregnation of chemical agents. While the compression of wood itself is not a subject of this review, the effect of a surface pre-treatment on its durability was deemed appropriate. Wu et al. impregnated poplar wood with a reactive waterborne acrylic resin by immerging a quarter of the wood blocks into the resin solution and applying a vacuum, leading to weight percent gains ranging from 1.1% to 4.7% [233][204]. Afterward, the impregnated surface was densified with a hot press under different temperatures ranging from 150 °C to 180 °C. At the highest loading of resin, the set-recovery of the impregnated wood was only 1.8%, while the control samples reached 73.0%. Similarly, Han partially soaked Scots pine for different durations in a furfuryl alcohol solution containing a maleic anhydride catalyst before pressing a single surface with a hot metal plate [234][205]. Under optimized conditions, the set-recovery of the densified wood decreased from 60% to 14%. Various impregnation agents were studied by Neyses et al. to achieve the same goal, although the results were not as satisfying [235][206]. Lafond et al. improved the embedment capacity of black spruce connectors through the impregnation of acrylates [236][207]. They found that a chemical retention of 7% could improve the bearing strength of the connector by 48% and their stiffness by 27%. Finally, the development of colored wood surfaces through the creation of complexes between phenolic extractives and metal ions was explored by Dagher et al. [237][208]. After simply applying a 1% ferric sulfate solution on the surface of different hardwoods with a foam roller applicator, different colors were developed for each species according to their phenolic extractives content.
Another way to protect wood by surface impregnation is to simply insert protective agents slightly under its surface. Harandi et al. brushed 5% and 10% solutions of poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVBVA) on silver fir to improve its mechanical properties [238][209]. They found that both solutions increased the water contact angle to 90%, reaching hydrophobicity, and improved the modulus of rupture (MOR), modulus of elasticity (MOE), plastic hardness and Martens hardness of the treated specimens. Although the more viscous 10% solution took more time to be absorb, it yielded equivalent MOR and MOE, as well as higher plastic hardness and Martens hardness than the 5% solution. Kumar et al. dipped Norway spruce blocks in a 1% solution of octadecyltrichlorosilane for 30 min to 120 min, yielding from 0.7% to 2.4% weight percentage gains [239,240][210][211]. They found that the treated specimens had very high static water contact angles (140–150°), a negligible water absorption through immersion, a lowered equilibrium moisture content when exposed to a high relative humidity (95%), an increased dimensional stability, and a reduced mass loss when exposed to the brown-rot fungi Coniophora puteana. The impregnation of poplar wood with K2CO3 and SiO2 solutions to improve its fire-retardancy was studied by He et al. [241][212]. They found that the limiting oxygen index (LOI) increased from 20.5% to 33.5% prior to the treatment, and only decreased to 30.5% after leaching. Thermogravimetric measurements showed that the mass loss decreased during the charring phase (63.2% to 47.4%) and the calcining stage (34.8% to 24.3%), while the char generation increased. Thermochromic wood veneers were prepared by Zhu et al. through the ultrasonic impregnation of a thermochromic dye and a color developer [242][213]. The treated wood, which was very dark, could return to its original color between 28 °C and 38 °C, while the discoloration was reversible between 34 °C and 22 °C. Other publications reported the surface impregnation of chemicals to decrease the wettability [57][28], flammability [243][214], mold [244,245][215][216] and mildew [246][217] degradation, and dimensional instability [247][218] of various wood substrates.

References

  1. Ma, T.; Li, L.; Wang, Q.; Guo, C. Construction of Intumescent Flame Retardant and Hydrophobic Coating on Wood Substrates Based on Thiol-Ene Click Chemistry without Photoinitiators. Compos. Part B Eng. 2019, 177, 107357.
  2. Wang, T.; Liu, T.; Ma, T.; Li, L.; Wang, Q.; Guo, C. Study on Degradation of Phosphorus and Nitrogen Composite UV-Cured Flame Retardant Coating on Wood Surface. Prog. Org. Coat. 2018, 124, 240–248.
  3. Mali, P.P.; Pawar, N.S.; Sonawane, N.S.; Patil, V.; Patil, R. UV Curable Flame Retardant Coating: A Novel Synthetic Approach of Trispiperazido Phosphate Based Reactive Diluent. Pigment Resin Technol. 2020, 50, 271–283.
  4. Wang, T.; Li, L.; Cao, Y.; Wang, Q.; Guo, C. Preparation and Flame Retardancy of Castor Oil Based UV-Cured Flame Retardant Coating Containing P/Si/S on Wood Surface. Ind. Crops Prod. 2019, 130, 562–570.
  5. Lokhande, G.; Chambhare, S.; Jagtap, R. Synthesis and Properties of Phosphate-Based Diacrylate Reactive Diluent Applied to UV-Curable Flame-Retardant Wood Coating. J. Coat. Technol. Res. 2017, 14, 255–266.
  6. Mulge, S.; Mestry, S.; Naik, D.; Mhaske, S. Phosphorus-Containing Reactive Agent for UV-Curable Flame-Retardant Wood Coating. J. Coat. Technol. Res. 2019, 16, 1493–1502.
  7. Paquet, C.; Schmitt, T.; Klemberg-Sapieha, J.E.; Morin, J.-F.; Landry, V. Self-Healing UV Curable Acrylate Coatings for Wood Finishing System, Part 1: Impact of the Formulation on Self-Healing Efficiency. Coatings 2020, 10, 770.
  8. Rawat, R.S.; Chouhan, N.; Talwar, M.; Diwan, R.K.; Tyagi, A.K. UV Coatings for Wooden Surfaces. Prog. Org. Coat. 2019, 135, 490–495.
  9. Wang, J.; Wu, H.; Liu, R.; Long, L.; Xu, J.; Chen, M.; Qiu, H. Preparation of a Fast Water-Based UV Cured Polyurethane-Acrylate Wood Coating and the Effect of Coating Amount on the Surface Properties of Oak (Quercus alba L.). Polymers 2019, 11, 1414.
  10. Raychura, A.J.; Dholakiya, B.Z.; Patel, K.I.; Jauhari, S. Development of Non-Traditional Vegetable-Oil-Based Two-Pack Polyurethane for Wood-Finished Coating: An Alternative Approach. ChemistrySelect 2018, 3, 10837–10842.
  11. Raychura, A.J.; Jauhari, S.; Prajapati, V.S.; Dholakiya, B.Z. Synthesis and Performance Evaluation of Vegetable Oil Based Wood Finish Polyurethane Coating. Bioresour. Technol. Rep. 2018, 3, 88–94.
  12. Lazim, A.M.; Azfaralariff, A.; Azman, I.; Arip, M.N.M.; Zubairi, S.I.; Mohd Kaus, N.H.; Nazir, N.; Mohamad, M.; Kamil, A.; Azzahari, A.D.; et al. Improving Wood Durability against G. Trabeum and C. Versicolor Using Starch Based Antifungal Coating from Dioscorea hispida sp. J. Taiwan Inst. Chem. Eng. 2020, 115, 242–250.
  13. Lazim, A.M.; Azman, I.; Yusoff, S.F.M.; Hassan, N.I.; Fazry, S.; Arip, M.N.M. Synthesis and Characterization of Dioscorea Hispida Sp. Tuber Starch-Polyacrylamide Wood Coating and Its Facile Inhibitory towards Pycnoporus Sanguineus and Coptotermes curvignathus. Prog. Org. Coat. 2016, 99, 182–190.
  14. Dixit, A.; Wazarkar, K.; Sabnis, A.S. Antimicrobial UV Curable Wood Coatings Based on Citric Acid. Pigment Resin Technol. 2021, in press.
  15. Kong, L.; Xu, D.; He, Z.; Wang, F.; Gui, S.; Fan, J.; Pan, X.; Dai, X.; Dong, X.; Liu, B.; et al. Nanocellulose-Reinforced Polyurethane for Waterborne Wood Coating. Molecules 2019, 24, 3151.
  16. Li, X.; Wang, D.; Zhao, L.; Hou, X.; Liu, L.; Feng, B.; Li, M.; Zheng, P.; Zhao, X.; Wei, S. UV LED Curable Epoxy Soybean-Oil-Based Waterborne PUA Resin for Wood Coatings. Prog. Org. Coat. 2021, 151, 105942.
  17. Szubert, K. Synthesis of Organofunctional Silane from Rapeseed Oil and Its Application as a Coating Material. Cellulose 2018, 25, 6269–6278.
  18. Mehta, L.B.; Wadgaonkar, K.K.; Jagtap, R.N. Synthesis and Characterization of High Bio-Based Content Unsaturated Polyester Resin for Wood Coating from Itaconic Acid: Effect of Various Reactive Diluents as an Alternative to Styrene. J. Dispers. Sci. Technol. 2019, 40, 756–765.
  19. Niu, K.; Song, K. Surface Coating and Interfacial Properties of Hot-Waxed Wood Using Modified Polyethylene Wax. Prog. Org. Coat. 2021, 150, 105947.
  20. Raphael, W.; Martel, T.; Landry, V.; Tavares, J.R. Surface Engineering of Wood Substrates to Impart Barrier Properties: A Photochemical Approach. Wood Sci. Technol. 2018, 52, 193–207.
  21. Merighi, S.; Mazzocchetti, L.; Benelli, T.; Maccaferri, E.; Zucchelli, A.; D’Amore, A.; Giorgini, L. A New Wood Surface Flame-Retardant Based on Poly-m-Aramid Electrospun Nanofibers. Polym. Eng. Sci. 2019, 59, 2541–2549.
  22. Janesch, J.; Arminger, B.; Gindl-Altmutter, W.; Hansmann, C. Superhydrophobic Coatings on Wood Made of Plant Oil and Natural Wax. Prog. Org. Coat. 2020, 148, 105891.
  23. Zhang, L.; Huang, Y.; Sun, P.; Hai, Y.; Jiang, S. A Self-Healing, Recyclable, and Degradable Fire-Retardant Gelatin-Based Biogel Coating for Green Buildings. Soft Matter 2021, 17, 5231–5239.
  24. Esfandiar, N.; Elmi, F.; Omidzahir, S. Study of the Structural Properties and Degradation of Coated Wood with Polydopamine/Hydroxyapatite/Chitosan Hybrid Nanocomposite in Seawater. Cellulose 2020, 27, 7779–7790.
  25. Liu, Y.; Hu, J. Investigation of Polystyrene-Based Microspheres from Different Copolymers and Their Structural Color Coatings on Wood Surface. Coatings 2021, 11, 14.
  26. Rosu, L.; Varganici, C.D.; Mustata, F.; Rosu, D.; Rosca, I.; Rusu, T. Epoxy Coatings Based on Modified Vegetable Oils for Wood Surface Protection against Fungal Degradation. ACS Appl. Mater. Interfaces 2020, 12, 14443–14458.
  27. .Ma, T.; Li, L.; Liu, Z.; Zhang, J.; Guo, C.; Wang, Q. A Facile Strategy to Construct Vegetable Oil-Based, Fire-Retardant, Transparent and Mussel Adhesive Intumescent Coating for Wood Substrates. Ind. Crops Prod. 2020, 154, 112628.
  28. Gordobil, O.; Herrera, R.; Llano-Ponte, R.; Labidi, J. Esterified Organosolv Lignin as Hydrophobic Agent for Use on Wood Products. Prog. Org. Coat. 2017, 103, 143–151.
  29. Zikeli, F.; Vinciguerra, V.; D’Annibale, A.; Capitani, D.; Romagnoli, M.; Mugnozza, G.S. Preparation of Lignin Nanoparticles from Wood Waste for Wood Surface Treatment. Nanomaterials 2019, 9, 281.
  30. Kluge, M.; Veigel, S.; Pinkl, S.; Henniges, U.; Zollfrank, C.; Rössler, A.; Gindl-Altmutter, W. Nanocellulosic Fillers for Waterborne Wood Coatings: Reinforcement Effect on Free-Standing Coating Films. Wood Sci. Technol. 2017, 51, 601–613.
  31. Yoo, Y.; Youngblood, J.P. Tung Oil Wood Finishes with Improved Weathering, Durability, and Scratch Performance by Addition of Cellulose Nanocrystals. ACS Appl. Mater. Interfaces 2017, 9, 24936–24946.
  32. Cheng, D.; Wen, Y.; An, X.; Zhu, X.; Ni, Y. TEMPO-Oxidized Cellulose Nanofibers (TOCNs) as a Green Reinforcement for Waterborne Polyurethane Coating (WPU) on Wood. Carbohydr. Polym. 2016, 151, 326–334.
  33. Cataldi, A.; Esposito Corcione, C.; Frigione, M.; Pegoretti, A. Photocurable Resin/Nanocellulose Composite Coatings for Wood Protection. Prog. Org. Coat. 2017, 106, 128–136.
  34. Yang, F.; Wu, Y.; Zhang, S.; Zhang, H.; Zhao, S.; Zhang, J.; Fei, B. Mechanical and Thermal Properties of Waterborne Polyurethane Coating Modified through One-Step Cellulose Nanocrystals/Graphene Materials Sols Method. Coatings 2020, 10, 40.
  35. Tian, Y.; Gao, Y.; Pan, X.; Liu, Q.; Wang, J.; Jin, M.; Li, J. Renewable UV-Curable Polyester Methacrylate/Cellulose Nanocrystals Composite Resin for Wood Waterproof Coating. Nanotechnology 2021, 32, 275703.
  36. Veigel, S.; Lems, E.M.; Grüll, G.; Hansmann, C.; Rosenau, T.; Zimmermann, T.; Gindl-Altmutter, W. Simple Green Route to Performance Improvement of Fully Bio-Based Linseed Oil Coating Using Nanofibrillated Cellulose. Polymers 2017, 9, 425.
  37. Kaboorani, A.; Auclair, N.; Riedl, B.; Landry, V. Mechanical Properties of UV-Cured Cellulose Nanocrystal (CNC) Nanocomposite Coating for Wood Furniture. Prog. Org. Coat. 2017, 104, 91–96.
  38. Kaboorani, A.; Auclair, N.; Riedl, B.; Landry, V. Physical and Morphological Properties of UV-Cured Cellulose Nanocrystal (CNC) Based Nanocomposite Coatings for Wood Furniture. Prog. Org. Coat. 2016, 93, 17–22.
  39. Kaboorani, A.; Auclair, N.; Riedl, B.; Hosseinaei, O.; Wang, S. Cellulose Nanocrystal (CNC)-Based Nanocomposites for UV Curable High-Solid Coating Systems. J. Coat. Technol. Res. 2017, 14, 1137–1145.
  40. Cheng, L.; Ren, S.; Lu, X. Application of Eco-Friendly waterborne Polyurethane Composite Coating Incorporated with Nano Cellulose Crystalline and Silver Nano Particles on Wood Antibacterial Board. Polymers 2020, 12, 407.
  41. Peng, Y.; Wang, Y.; Chen, P.; Wang, W.; Cao, J. Enhancing Weathering Resistance of Wood by Using Bark Extractives as Natural Photostabilizers in Polyurethane-Acrylate Coating. Prog. Org. Coat. 2020, 145, 105665.
  42. Özgenç, Ö.; Durmaz, S.; Şahin, S.; Boyaci, İ.H. Evaluation of the Weathering Resistance of Waterborne Acrylic- and Alkyd-Based Coatings Containing HALS, UV Absorber, and Bark Extracts on Wood Surfaces. J. Coat. Technol. Res. 2020, 17, 461–475.
  43. Grigsby, W.J. Photooxidative Stability Provided by Condensed Tannin Additives in Acrylic-Based Surface Coatings on Exterior Exposure. J. Coat. Technol. Res. 2018, 15, 1273–1282.
  44. Tomak, E.D.; Yazici, O.A.; Sam Parmak, E.D.; Gonultas, O. Influence of Tannin Containing Coatings on Weathering Resistance of Wood: Combination with Zinc and Cerium Oxide Nanoparticles. Polym. Degrad. Stab. 2018, 152, 289–296.
  45. Tomak, E.D.; Arican, F.; Gonultas, O.; Sam Parmak, E.D. Influence of Tannin Containing Coatings on Weathering Resistance of Wood: Water Based Transparent and Opaque Coatings. Polym. Degrad. Stab. 2018, 151, 152–159.
  46. Huang, Y.; Feng, Q.; Ye, C.; Nair, S.S.; Yan, N. Incorporation of Ligno-Cellulose Nanofibrils and Bark Extractives in Water-Based Coatings for Improved Wood Protection. Prog. Org. Coat. 2020, 138, 105210.
  47. Yan, X.; Wang, L.; Qian, X. Effect of High-Temperature Calcined Wheat Straw Powder after Lignin Removal on Properties of Waterborne Wood Coatings. Coatings 2019, 9, 444.
  48. Zhu, X.; Liu, Y.; Li, Z.; Wang, W. Thermochromic Microcapsules with Highly Transparent Shells Obtained through In-Situ Polymerization of Urea Formaldehyde around Thermochromic Cores for Smart Wood Coatings. Sci. Rep. 2018, 8, 4015.
  49. Yan, X.; Wang, L.; Qian, X. Effect of Coating Process on Performance of Reversible Thermochromic Waterborne Coatings for Chinese Fir. Coatings 2020, 10, 223.
  50. Li, Y.; Li, J. Fabrication of Reversible Thermoresponsive Thin Films on Wood Surfaces with Hydrophobic Performance. Prog. Org. Coat. 2018, 119, 15–22.
  51. Li, Y.; Hui, B.; Li, G.; Li, J. Fabrication of Smart Wood with Reversible Thermoresponsive Performance. J. Mater. Sci. 2017, 52, 7688–7697.
  52. Yan, X.; Peng, W. Preparation of Microcapsules of Urea Formaldehyde Resin Coated Waterborne Coatings and Their Effect on Properties of Wood Crackle Coating. Coatings 2020, 10, 764.
  53. Queant, C.; Blanchet, P.; Landry, V.; Schorr, D. Effect of Adding UV Absorbers Embedded in Carbonate Calcium Templates Covered with Light Responsive Polymer into a Clear Wood Coating. Coatings 2018, 8, 265.
  54. Yan, X.; Wang, L.; Qian, X. Effect of Urea-Formaldehyde-Coated Epoxy Microcapsule Modification on Gloss, Toughness and Chromatic Distortion of Acrylic Copolymers Waterborne Coating. Coatings 2019, 9, 239.
  55. Hermann, A.; Burr, D.; Landry, V. Comparative Study of the Impact of Additives against Oxygen Inhibition on Pendulum Hardness and Abrasion Resistance for UV-Curable Wood Finishes. Prog. Org. Coat. 2021, 156, 106266.
  56. Jia, S.; Lu, X.; Luo, S.; Qing, Y.; Yan, N.; Wu, Y. Efficiently Texturing Hierarchical Epoxy Layer for Smart Superhydrophobic Surfaces with Excellent Durability and Exceptional Stability Exposed to Fire. Chem. Eng. J. 2018, 348, 212–223.
  57. Wu, Y.; Wu, X.; Yang, F.; Ye, J. Preparation and Characterization of Waterborne UV Lacquer Product Modified by Zinc Oxide with Flower Shape. Polymers 2020, 12, 668.
  58. Zhan, K.; Xia, S.; Lu, Q.; Cheng, R.; Jiang, H.; Yi, T.; Morrell, J.; Yang, L.; Xie, L.; Lei, H.; et al. Superhydrophobic Wood Surface Fabricated by Cu2O Nano-Particles and Stearic Acid: Its Acid/Alkali and Wear Resistance. Holzforschung 2021, 75, 917–931.
  59. Zhan, K.; Lu, Q.; Xia, S.; Guo, C.; Zhao, S.; Gao, W.; Yang, L.; Morrell, J.J.; Yi, T.; Xie, L.; et al. A Cost Effective Strategy to Fabricate @Cu2O Hierarchical Structure on Wood Surface: Aimed at Superhydrophobic Modification. Wood Sci. Technol. 2021, 55, 565–583.
  60. Sevda, B.T.; Ayfer, D.C.; Turgay, O. The Synergistic Effect of Intumescent Coating Containing Titanium Dioxide and Antimony Trioxide onto Spruce and Alder Wood Species. J. Build. Eng. 2020, 31, 101407.
  61. Guo, S.; Wang, D.; Shi, J.; Li, X.; Feng, B.; Meng, L.; Cai, Z.; Qiu, H.; Wei, S. Study on Waterborne Acrylate Coatings Modified with Biomass Silicon. Prog. Org. Coat. 2019, 135, 601–607.
  62. Pantano, D.; Neubauer, N.; Navratilova, J.; Scifo, L.; Civardi, C.; Stone, V.; Von Der Kammer, F.; Müller, P.; Sobrido, M.S.; Angeletti, B.; et al. Transformations of Nanoenabled Copper Formulations Govern Release, Antifungal Effectiveness, and Sustainability throughout the Wood Protection Lifecycle. Environ. Sci. Technol. 2018, 52, 1128–1138.
  63. Silva-Castro, I.; Casados-Sanz, M.; Alonso-Cortés, A.L.; Martín-Ramos, P.; Martín-Gil, J.; Acuña-Rello, L. Chitosan-Based Coatings to Prevent the Decay of Populus spp. Wood Caused by Trametes Versicolor. Coatings 2018, 8, 415.
  64. Boivin, G.; Ritcey, A.M.; Landry, V. The Effect of Silver Nanoparticles on the Black-Stain Resistance of Acrylic Resin for Translucent Wood Coating Application. BioResources 2019, 14, 6353–6369.
  65. Moya, R.; Rodríguez-Zúñiga, A.; Vega-Baudrit, J.; Puente-Urbina, A. Effects of Adding TiO2 Nanoparticles to a Water-Based Varnish for Wood Applied to Nine Tropical Woods of Costa Rica Exposed to Natural and Accelerated Weathering. J. Coat. Technol. Res. 2017, 14, 141–152.
  66. Yan, X.-X.; Cai, Y.-T.; Xu, G.-Y.; Xu, W. Mechanical and Optical Properties of Waterborne UV Curing Coating Modified by Silica. In Proceedings of the 4th Annual International Conference on Material Science and Engineering (ICMSE 2016), Guangzhou, China, 17–19 June 2016; pp. 370–375.
  67. Weththimuni, M.L.; Capsoni, D.; Malagodi, M.; Milanese, C.; Licchelli, M. Shellac/Nanoparticles Dispersions as Protective Materials for Wood. Appl. Phys. A Mater. Sci. Process. 2016, 122, 1058.
  68. Atienza, R.A.G.; Cruz, T.J.F. Utilizing Philippine Cupped Oyster (Crassostrea Iredalei) Shell Powder and Waterborne Acrylic Resin as a Fire Retardant Coating for Marine Wood. In Proceedings of the 9th IEEE Integrated STEM Education Conference (ISEC 2019), Princeton, NJ, USA, 16 March 2019; pp. 9–10.
  69. Wu, J.; Wang, M.; Guo, H. Synergistic Flame Retardant Effects of Different Zeolites on Intumescent Fire Retardant Coating for Wood. BioResources 2017, 12, 5369–5382.
  70. Esmailpour, A.; Majidi, R.; Taghiyari, H.R.; Ganjkhani, M.; Armaki, S.M.M.; Papadopoulos, A.N. Improving Fire Retardancy of Beechwood by Graphene. Polymers 2020, 12, 303.
  71. Taghiyari, H.R.; Tajvidi, M.; Soltani, A.; Esmailpour, A.; Khodadoosti, G.; Jafarzadeh, H.; Militz, H.; Papadopoulos, A.N. Improving Fire Retardancy of Unheated and Heat-Treated Fir Wood by Nano-Sepiolite. Eur. J. Wood Wood Prod. 2021, 79, 841–849.
  72. Kolya, H.; Kang, C.W. Polyvinyl Acetate/Reduced Graphene Oxide-Poly (Diallyl Dimethylammonium Chloride) Composite Coated Wood Surface Reveals Improved Hydrophobicity. Prog. Org. Coat. 2021, 156, 106253.
  73. Chen, B.; Jia, Y.; Zhang, M.; Li, X.; Yang, J.; Zhang, X. Facile Modification of Sepiolite and Its Application in Superhydrophobic Coatings. Appl. Clay Sci. 2019, 174, 1–9.
  74. Isaji, S.; Kojima, Y. Application of Copper Monoethanolamine Solutions as Primers for Semitransparent Exterior Wood Stains. Eur. J. Wood Wood Prod. 2017, 75, 305–314.
  75. Yang, Y.; Shan, L.; Shen, H.; Qiu, J. Manufacturing of Robust Superhydrophobic Wood Surfaces Based on PEG–Functionalized SiO2/PVA/PAA/Fluoropolymer Hybrid Transparent Coating. Prog. Org. Coat. 2021, 154, 106186.
  76. Lozhechnikova, A.; Bellanger, H.; Michen, B.; Burgert, I.; Österberg, M. Surfactant-Free Carnauba Wax Dispersion and Its Use for Layer-by-Layer Assembled Protective Surface Coatings on Wood. Appl. Surf. Sci. 2017, 396, 1273–1281.
  77. Lu, P.; Yun, H.; Zhang, W.; Tu, D.; Hu, C.; Cherdchim, B. A Facile Method of Superhydrophobic Coating on Rubberwood to Improve Its Anti-Mildew Performance. BioResources 2019, 14, 7111–7121.
  78. Kong, L.; Kong, X.; Ji, Z.; Wang, X.; Zhang, X. Large-Scale Fabrication of a Robust Superhydrophobic Thermal Energy Storage Sprayable Coating Based on Polymer Nanotubes. ACS Appl. Mater. Interfaces 2020, 12, 49694–49704.
  79. Janesch, J.; Czabany, I.; Hansmann, C.; Mautner, A.; Rosenau, T.; Gindl-Altmutter, W. Transparent Layer-by-Layer Coatings Based on Biopolymers and CeO2 to Protect Wood from UV Light. Prog. Org. Coat. 2020, 138, 105409.
  80. Weththimuni, M.L.; Capsoni, D.; Malagodi, M.; Licchelli, M. Improving Wood Resistance to Decay by Nanostructured ZnO-Based Treatments. J. Nanomater. 2019, 2019, 6715756.
  81. Tu, K.; Wang, X.; Kong, L.; Guan, H. Facile Preparation of Mechanically Durable, Self-Healing and Multifunctional Superhydrophobic Surfaces on Solid Wood. Mater. Des. 2018, 140, 30–36.
  82. Yang, R.; Zuo, S.; Song, B.; Mao, H.; Huang, Z.; Wu, Y.; Cai, L.; Ge, S.; Lian, H.; Xia, C. Hollow Mesoporous Microspheres Coating for Super-Hydrophobicity Wood with High Thermostability and Abrasion Performance. Polymers 2020, 12, 2856.
  83. Liu, W.; Hu, C.; Zhang, W.; Liu, Z.; Shu, J.; Gu, J. Modification of Birch Wood Surface with Silane Coupling Agents for Adhesion Improvement of UV-Curable Ink. Prog. Org. Coat. 2020, 148, 105833.
  84. Yue, D.; Feng, Q.; Huang, X.; Zhang, X.; Chen, H. In Situ Fabrication of a Superhydrophobic ORMOSIL Coating on Wood by an Ammonia-HMDS Vapor Treatment. Coatings 2019, 9, 556.
  85. Shah, S.M.; Zulfiqar, U.; Hussain, S.Z.; Ahmad, I.; Habib-ur-Rehman; Hussain, I.; Subhani, T. A Durable Superhydrophobic Coating for the Protection of Wood Materials. Mater. Lett. 2017, 203, 17–20.
  86. Ou, J.; Zhao, G.; Wang, F.; Li, W.; Lei, S.; Fang, X.; Siddiqui, A.R.; Xia, Y.; Amirfazli, A. Durable Superhydrophobic Wood via One-Step Immersion in Composite Silane Solution. ACS Omega 2021, 6, 7266–7274.
  87. Jia, S.; Lu, Y.; Luo, S.; Qing, Y.; Wu, Y.; Parkin, I.P. Thermally-Induced All-Damage-Healable Superhydrophobic Surface with Photocatalytic Performance from Hierarchical BiOCl. Chem. Eng. J. 2019, 366, 439–448.
  88. Jia, S.; Liu, M.; Wu, Y.; Luo, S.; Qing, Y.; Chen, H. Facile and Scalable Preparation of Highly Wear-Resistance Superhydrophobic Surface on Wood Substrates Using Silica Nanoparticles Modified by VTES. Appl. Surf. Sci. 2016, 386, 115–124.
  89. Jia, S.; Chen, H.; Luo, S.; Qing, Y.; Deng, S.; Yan, N.; Wu, Y. One-Step Approach to Prepare Superhydrophobic Wood with Enhanced Mechanical and Chemical Durability: Driving of Alkali. Appl. Surf. Sci. 2018, 455, 115–122.
  90. Xing, Y.; Xue, Y.; Song, J.; Sun, Y.; Huang, L.; Liu, X.; Sun, J. Superhydrophobic Coatings on Wood Substrate for Self-Cleaning and EMI Shielding. Appl. Surf. Sci. 2018, 436, 865–872.
  91. Wang, Y.; Yan, W.; Frey, M.; Vidiella del Blanco, M.; Schubert, M.; Adobes-Vidal, M.; Cabane, E. Liquid-Like SiO2—g-PDMS Coatings on Wood Surfaces with Underwater Durability, Antifouling, Antismudge, and Self-Healing Properties. Adv. Sustain. Syst. 2019, 3, 1800070.
  92. Yao, Q.; Wang, C.; Fan, B.; Wang, H.; Sun, Q.; Jin, C.; Zhang, H. One-Step Solvothermal Deposition of ZnO Nanorod Arrays on a Wood Surface for Robust Superamphiphobic Performance and Superior Ultraviolet Resistance. Sci. Rep. 2016, 6, 35505.
  93. Kong, L.; Tu, K.; Guan, H.; Wang, X. Growth of High-Density ZnO Nanorods on Wood with Enhanced Photostability, Flame Retardancy and Water Repellency. Appl. Surf. Sci. 2017, 407, 479–484.
  94. Bao, W.; Zhang, M.; Jia, Z.; Jiao, Y.; Cai, L.; Liang, D.; Li, J. Cu Thin Films on Wood Surface for Robust Superhydrophobicity by Magnetron Sputtering Treatment with Perfluorocarboxylic Acid. Eur. J. Wood Wood Prod. 2019, 77, 115–123.
  95. Gao, J.; Lin, W.; Lin, S.; Zhang, X.; Yang, W.; Li, R. Environment-Friendly and Two-Component Method for Fabrication of Highly Hydrophobic Wood Using Poly(Methylhydrogen)Siloxane. Polymers 2021, 13, 124.
  96. Lu, X.; Hu, Y. Layer-by-Layer Deposition of TiO2 Nanoparticles in the Wood Surface and Its Superhydrophobic Performance. BioResources 2016, 11, 4605–4620.
  97. Zhang, X.; Xiao, F.; Feng, Q.; Zheng, J.; Chen, C.; Chen, H.; Yang, W. Preparation of SiO2 Nanoparticles with Adjustable Size for Fabrication of SiO2/PMHS ORMOSIL Superhydrophobic Surface on Cellulose-Based Substrates. Prog. Org. Coat. 2020, 138, 105384.
  98. Guo, H.; Fuchs, P.; Casdorff, K.; Michen, B.; Chanana, M.; Hagendorfer, H.; Romanyuk, Y.E.; Burgert, I. Bio-Inspired Superhydrophobic and Omniphobic Wood Surfaces. Adv. Mater. Interfaces 2017, 4, 1600289.
  99. Yue, D.; Lin, S.; Cao, M.; Lin, W.; Zhang, X. Fabrication of Transparent and Durable Superhydrophobic Polysiloxane/SiO2 Coating on the Wood Surface. Cellulose 2021, 28, 3745–3758.
  100. Pandit, S.K.; Tudu, B.K.; Mishra, I.M.; Kumar, A. Development of Stain Resistant, Superhydrophobic and Self-Cleaning Coating on Wood Surface. Prog. Org. Coat. 2020, 139, 105453.
  101. Xia, M.; Yang, T.; Chen, S.; Yuan, G. Fabrication of Superhydrophobic Eucalyptus Wood Surface with Self-Cleaning Performance in Air and Oil Environment and High Durability. Colloids Interface Sci. Commun. 2020, 36, 100264.
  102. Kumar, A.; Tudu, B.K.; Pandit, S.K. Development of Novel Anti-wetting Coating on Cellulosic Surface Using Low Carbon Butyric Acid. Cellulose 2021, 28, 4825–4834.
  103. Tu, K.; Kong, L.; Wang, X.; Liu, J. Semitransparent, Durable Superhydrophobic Polydimethylsiloxane/SiO2 Nanocomposite Coatings on Varnished Wood. Holzforschung 2016, 70, 1039–1045.
  104. Wang, J.; Lu, Y.; Chu, Q.; Ma, C.; Cai, L.; Shen, Z.; Chen, H. Facile Construction of Superhydrophobic Surfaces by Coating Fluoroalkylsilane/Silica Composite on a Modified Hierarchical Structure of Wood. Polymers 2020, 12, 813.
  105. Guo, B.; Liu, Y.; Zhang, Q.; Wang, F.; Wang, Q.; Liu, Y.; Li, J.; Yu, H. Efficient Flame-Retardant and Smoke-Suppression Properties of Mg-Al-Layered Double-Hydroxide Nanostructures on Wood Substrate. ACS Appl. Mater. Interfaces 2017, 9, 23039–23047.
  106. Wang, K.; Dong, Y.; Zhang, W.; Zhang, S.; Li, J. Prearation of Stable Superhydrophobic Coatings on Wood Substrate Surfaces via Mussel-Inspired Polydopamine and Electroless Deposition Methods. Polymers 2017, 9, 218.
  107. Huang, J.; Lyu, S.; Fu, F.; Chang, H.; Wang, S. Preparation of Superhydrophobic Coating with Excellent Abrasion Resistance and Durability Using Nanofibrillated Cellulose. RSC Adv. 2016, 6, 106194–106200.
  108. Huang, J.; Lyu, S.; Fu, F.; Wu, Y.; Wang, S. Green Preparation of a Cellulose Nanocrystals/Polyvinyl Alcohol Composite Superhydrophobic Coating. RSC Adv. 2017, 7, 20152–20159.
  109. Huang, J.; Wang, S.; Lyu, S. Facile Preparation of a Robust and Durable Superhydrophobic Coating Using Biodegradable Lignin-Coated Cellulose Nanocrystal Particles. Materials 2017, 10, 1080.
  110. Yang, Y.; Shen, H.; Qiu, J. Fabrication of Biomimetic Robust Self-Cleaning Superhydrophobic Wood with Canna-Leaf-like Micro/Nanostructure through Morph-Genetic Method Improved Water-, UV-, and Corrosion Resistance Properties. J. Mol. Struct. 2020, 1219, 128616.
  111. Yang, Y.; He, H.; Li, Y.; Qiu, J. Using Nanoimprint Lithography to Create Robust, Buoyant, Superhydrophobic PVB/SiO2 Coatings on Wood Surfaces Inspired by Red Roses Petal. Sci. Rep. 2019, 9, 9961.
  112. Chen, Y.; Wang, H.; Yao, Q.; Fan, B.; Wang, C.; Xiong, Y.; Jin, C.; Sun, Q. Biomimetic Taro Leaf-like Films Decorated on Wood Surfaces Using Soft Lithography for Superparamagnetic and Superhydrophobic Performance. J. Mater. Sci. 2017, 52, 7428–7438.
  113. Gan, W.; Gao, L.; Zhang, W.; Li, J.; Zhan, X. Fabrication of Microwave Absorbing CoFe2O4 Coatings with Robust Superhydrophobicity on Natural Wood Surfaces. Ceram. Int. 2016, 42, 13199–13206.
  114. Wang, K.; Wang, Z.; Dong, Y.; Zhang, S.; Li, J. Coordination-Driven Controlled Assembly of Polyphenol-Metal Green Coating on Wood Micro-Grooved Surfaces: A Novel Approach to Stable Superhydrophobicity. Polymers 2017, 9, 347.
  115. Tang, T.; Fu, Y. Formation of Chitosan/Sodium Phytate/Nano-Fe3O4 Magnetic Coatings on Wood Surfaces via Layer-by-Layer Self-Assembly. Coatings 2020, 10, 51.
  116. Uddin, M.; Kiviranta, K.; Suvanto, S.; Alvila, L.; Leskinen, J.; Lappalainen, R.; Haapala, A. Casein-Magnesium Composite as an Intumescent Fire Retardant Coating for Wood. Fire Saf. J. 2020, 112, 102943.
  117. Xie, H.; Lai, X.; Li, H.; Gao, J.; Zeng, X.; Huang, X.; Lin, X. A Highly Efficient Flame Retardant Nacre-Inspired Nanocoating with Ultrasensitive Fire-Warning and Self-Healing Capabilities. Chem. Eng. J. 2019, 369, 8–17.
  118. Sahin, H.T.; Mantanis, G.I. Colour Changes of Pine and Fir Wood Treated with Several Titanium and Zinc-Oxide Based Nanocompounds. Adv. For. Lett. 2016, 5, 17–23.
  119. Nair, S.; Nagarajappa, G.B.; Pandey, K.K. UV Stabilization of Wood by Nano Metal Oxides Dispersed in Propylene Glycol. J. Photochem. Photobiol. B Biol. 2018, 183, 1–10.
  120. Wang, Y.; Wu, X.; Wang, Y.; Tian, Y.; Mu, H.; Li, J. Hydrophobic and UV-Resistant Properties of Environmentally Friendly Nano-ZnO-Coated Wood. Holzforschung 2021, 75, 138–147.
  121. Qu, L.; Rahimi, S.; Qian, J.; He, L.; He, Z.; Yi, S. Preparation and Characterization of Hydrophobic Coatings on Wood Surfaces by a Sol-Gel Method and Post-Aging Heat Treatment. Polym. Degrad. Stab. 2021, 183, 109429.
  122. Kanokwijitsilp, T.; Traiperm, P.; Osotchan, T.; Srikhirin, T. Development of Abrasion Resistance SiO2 Nanocomposite Coating for Teak Wood. Prog. Org. Coat. 2016, 93, 118–126.
  123. Fu, Y.; Liu, X.; Cheng, F.; Sun, J.; Qin, Z. Modification of the Wood Surface Properties of Tsoongiodendron Odorum Chun with Silicon Dioxide by a Sol-Gel Method. BioResources 2016, 11, 10273–10285.
  124. Xuan, L.; Fu, Y.; Liu, Z.; Wei, P.; Wu, L. Hydrophobicity and Photocatalytic Activity of a Wood Surface Coated with a Fe3+-Doped SiO2 /TiO2 Film. Materials 2018, 11, 2594.
  125. Liu, Z.; Xuan, L.; Fu, Y. Aging Resistance and Photocatalytic Activity of a Wood Surface Coated with a Zr4+-Doped SiO2/TiO2 Film. BioResources 2020, 15, 6404–6419.
  126. Qian, T.; Dang, B.; Chen, Y.; Jin, C.; Qian, J.; Sun, Q. Fabrication of Magnetic Phase Change N-Eicosane @ Fe3O4/SiO2 Microcapsules on Wood Surface via Sol-Gel Method. J. Alloys Compd. 2019, 772, 871–876.
  127. Guo, H.; Fuchs, P.; Cabane, E.; Michen, B.; Hagendorfer, H.; Romanyuk, Y.E.; Burgert, I. UV-Protection of Wood Surfaces by Controlled Morphology Fine-Tuning of ZnO Nanostructures. Holzforschung 2016, 70, 699–708.
  128. Qing, Y.; Liu, M.; Wu, Y.; Jia, S.; Wang, S.; Li, X. Investigation on Stability and Moisture Absorption of Superhydrophobic Wood under Alternating Humidity and Temperature Conditions. Results Phys. 2017, 7, 1705–1711.
  129. Pori, P.; Vilčnik, A.; Petrič, M.; Sever Škapin, A.; Mihelčič, M.; Šurca Vuk, A.; Novak, U.; Orel, B. Structural Studies of TiO2 /Wood Coatings Prepared by Hydrothermal Deposition of Rutile Particles from TiCl4 Aqueous Solutions on Spruce (Picea Abies) Wood. Appl. Surf. Sci. 2016, 372, 125–138.
  130. Gan, W.; Gao, L.; Liu, Y.; Zhan, X.; Li, J. The Magnetic, Mechanical, Thermal Properties and Uv Resistance of CoFe2O4/SiO2-Coated Film on Wood. J. Wood Chem. Technol. 2016, 36, 94–104.
  131. Sun, M.; Song, K. Low Temperature Hydrothermal Fabrication of Tungsten Trioxide on the Surface of Wood with Photochromic and Superhydrophobic Properties. BioResources 2018, 13, 1075–1087.
  132. Sun, M.; Song, K. Effect of Tungsten Trioxide Nanosheets Prepared under Low-Energy State on Wood Surface Modification. BioResources 2019, 14, 9146–9158.
  133. Hui, B.; Li, G.; Li, J.; Via, B.K. Hydrothermal Deposition and Photoresponsive Properties of WO3 Thin Films on Wood Surfaces Using Ethanol as an Assistant Agent. J. Taiwan Inst. Chem. Eng. 2016, 64, 336–342.
  134. Hui, B.; Li, J. Low-Temperature Synthesis of Hierarchical Flower-like Hexagonal Molybdenum Trioxide Films on Wood Surfaces and Their Light-Driven Molecular Responses. J. Mater. Sci. 2016, 51, 10926–10934.
  135. Wang, H.; Yao, Q.; Wang, C.; Ma, Z.; Sun, Q.; Fan, B.; Jin, C.; Chen, Y. Hydrothermal Synthesis of Nanooctahedra MnFe2O4 onto the Wood Surface with Soft Magnetism, Fire Resistance and Electromagnetic Wave Absorption. Nanomaterials 2017, 7, 118.
  136. Wang, H.; Yao, Q.; Wang, C.; Fan, B.; Sun, Q.; Jin, C.; Xiong, Y.; Chen, Y. A Simple, One-Step Hydrothermal Approach to Durable and Robust Superparamagnetic, Superhydrophobic and Electromagnetic Wave-Absorbing Wood. Sci. Rep. 2016, 6, 35549.
  137. Belykh, S.; Novoselova, J.; Novoselov, D. Fire Retardant Coating for Wood Using Resource-Saving Technologies. In International Scientific Conference Energy Management of Municipal Facilities and Sustainable Energy Technologies EMMFT 2018 Volume 1; Murgul, V., Pasetti, M., Eds.; Springer: Singapore, 2020; pp. 673–681. ISBN 978-3-030-19756-8.
  138. Pan, Y.; Yin, D.; Surigala, S.; Hao, Y.; Xing, D.; Hao, S.; Yu, X.; Yu, H.; Huang, J. Performance and Preparation of the Electroless Ni Wood-Based Composites. BioResources 2020, 15, 7517–7531.
  139. Pan, Y.; Yin, D.; Yu, X.; Hao, N.; Huang, J. Multilayer-Structured Wood Electroless Cu-Ni Composite Coatings for Electromagnetic Interference Shielding. Coatings 2020, 10, 740.
  140. Pan, Y.F.; Guo, Z.Q.; Guo, T.C.; Wang, X.; Huang, J.T. The Preparation, Characterization, and Influence of Multiple Electroless Nickel-Phosphorus (Ni-P) Hollow Composite Coatings on Micro-Nano Cellulose Fibers. Surf. Coat. Technol. 2016, 298, 33–38.
  141. Wang, N.; Wang, Q.; Xu, S.; Qu, L.; Shi, Z. Robust Superhydrophobic Wood Surfaces with Mechanical Durability. Colloids Surfaces A Physicochem. Eng. Asp. 2021, 608, 125624.
  142. Łukawski, D.; Lekawa-Raus, A.; Lisiecki, F.; Koziol, K.; Dudkowiak, A. Towards the Development of Superhydrophobic Carbon Nanomaterial Coatings on Wood. Prog. Org. Coat. 2018, 125, 23–31.
  143. Yuan, B.; Ji, X.; Nguyen, T.T.; Huang, Z.; Guo, M. UV Protection of Wood Surfaces by Graphitic Carbon Nitride Nanosheets. Appl. Surf. Sci. 2019, 467–468, 1070–1075.
  144. Liu, J.; Kutty, R.G.; Zheng, Q.; Eswariah, V.; Sreejith, S.; Liu, Z. Hexagonal Boron Nitride Nanosheets as High-Performance Binder-Free Fire-Resistant Wood Coatings. Small 2017, 13, 1–6.
  145. Chu, P.K.; Chen, J.Y.; Wang, L.P.; Huang, N. Plasma-Surface Modification of Biomaterials. Mater. Sci. Eng. R Rep. 2002, 36, 143–206.
  146. Petrič, M. Surface Modification of Wood: A Critical Review. Rev. Adhes. Adhes. 2013, 1, 216–247.
  147. Haase, J.G.; Leung, L.H.; Evans, P.D. Plasma Pre-Treatments to Improve the Weather Resistance of Polyurethane Coatings on Black Spruce Wood. Coatings 2019, 9, 8.
  148. Žigon, J.; Pavlič, M.; Kibleur, P.; Van Den Bulcke, J.; Petrič, M.; Van Acker, J.; Dahle, S. Treatment of Wood with Atmospheric Plasma Discharge: Study of the Treatment Process, Dynamic Wettability and Interactions with a Waterborne Coating. Holzforschung 2020, 75, 603–613.
  149. Žigon, J.; Petrič, M.; Dahle, S. Artificially Aged Spruce and Beech Wood Surfaces Reactivated Using FE-DBD Atmospheric Plasma. Holzforschung 2019, 73, 1069–1081.
  150. de Cademartori, P.H.G.; Nisgoski, S.; Magalhães, W.L.E.; de Muniz, G.I.B. Surface Wettability of Brazilian Tropical Wood Flooring Treated with He Plasma. Maderas Cienc. Tecnol. 2016, 18, 715–722.
  151. Žigon, J.; Kovač, J.; Zaplotnik, R.; Saražin, J.; Šernek, M.; Petrič, M.; Dahle, S. Enhancement of Strength of Adhesive Bond between Wood and Metal Using Atmospheric Plasma Treatment. Cellulose 2020, 27, 6411–6424.
  152. Ivanov, I.; Dineff, P. Plasma-Aided Surface Finishing for Flame Retardation of Wood Through the Use of Surfactants. Mach. Technol. Mater. 2016, 10, 49–52.
  153. Novák, I.; Sedliačik, J.; Kleinová, A.; Matyasovsky, J. Oak Wood Pre-Treated by Cold Plasma. Ann. Warsaw Univ. Life Sci. SGGW For. Wood Technol. 2018, 104, 163–168.
  154. Novák, I.; Sedliačik, J.; Kleinova, A.; Mstyasovsky, J.; Jurkovič, P. Discharge Plasma Treatment of Wood Surfaces. Ann. Warsaw Univ. Life Sci. SGGW For. Wood Technol. 2018, 104, 169–173.
  155. Novák, I.; Sedliačik, J.; Chodák, I.; Mičusik, M.; Matyasovsky, J.; Jurkovič, P. Modification of Wood by Radio-Frequency Discharge Plasma. Ann. Warsaw Univ. Life Sci. SGGW For. Wood Technol. 2019, 105, 85–90.
  156. Novák, I.; Sedliačik, J.; Krystofiak, T.; Lis, B.; Popelka, A.; Kleinová, A.; Matyašovský, J.; Jurkovič, P.; Bekhta, P. Study of Wood Surface Pre-Treatment by Radio-Frequency Discharge Plasma. Drewno 2019, 62, 81–91.
  157. Jablonsky, M.; Smatko, L.; Botkova, M.; Tino, R.; Slma, J. Modification of Wood Wettability (European Beech) by Diffuse Coplanar Surface Barrier Discharge Plasma. Cellul. Chem. Technol. 2016, 50, 41–48.
  158. Tang, Z.; Xie, L.; Hess, D.W.; Breedveld, V. Fabrication of Amphiphobic Softwood and Hardwood by Treatment with Non-Fluorinated Chemicals. Wood Sci. Technol. 2017, 51, 97–113.
  159. Žigon, J.; Petrič, M.; Dahle, S. Dielectric and Surface Properties of Wood Modified with NaCl Aqueous Solutions and Treated with FE-DBD Atmospheric Plasma. Eur. J. Wood Wood Prod. 2021, 79, 1117–1128.
  160. Žigon, J.; Dahle, S. Improvement of Plasma Treatment Efficiency of Wood and Coating Process by Sodium Chloride Aqueous Solutions. Pro Ligno 2019, 15, 260–267.
  161. Peng, X.; Zhang, Z. Improvement of Paint Adhesion of Environmentally Friendly Paint Film on Wood Surface by Plasma Treatment. Prog. Org. Coat. 2019, 134, 255–263.
  162. Dahle, S.; Meuthen, J.; Gustus, R.; Prowald, A.; Viöl, W.; Maus-Friedrichs, W. Superhydrophilic Coating of Pine Wood by Plasma Functionalization of Self-Assembled Polystyrene Spheres. Coatings 2021, 11, 114.
  163. Gospodinova, D.N.; Dineff, P.D. Energy Efficiency of Atmospheric Pressure Plasma-Aided Porous Media Surface Finishing. IOP Conf. Ser. Mater. Sci. Eng. 2019, 618, 012019.
  164. Volokitin, G.; Skripnikova, N.; Volokitin, O.; Shekhovtsov, V.; Balobanov, P.; Pfuch, A. Modification of Wood Properties by Highly-Concentrated Plasma Flow. Key Eng. Mater. 2018, 781, 88–92.
  165. Chen, W.; Zhou, X.; Zhang, X.; Bian, J.; Shi, S.; Nguyen, T.; Chen, M.; Wan, J. Fast Enhancement on Hydrophobicity of Poplar Wood Surface Using Low-Pressure Dielectric Barrier Discharges (DBD) Plasma. Appl. Surf. Sci. 2017, 407, 412–417.
  166. Wallenhorst, L.; Gurău, L.; Gellerich, A.; Militz, H.; Ohms, G.; Viöl, W. UV-Blocking Properties of Zn/ZnO Coatings on Wood Deposited by Cold Plasma Spraying at Atmospheric Pressure. Appl. Surf. Sci. 2018, 434, 1183–1192.
  167. Profili, J.; Levasseur, O.; Koronai, A.; Stafford, L.; Gherardi, N. Deposition of Nanocomposite Coatings on Wood Using Cold Discharges at Atmospheric Pressure. Surf. Coat. Technol. 2017, 309, 729–737.
  168. Tuominen, M.; Teisala, H.; Haapanen, J.; Mäkelä, J.M.; Honkanen, M.; Vippola, M.; Bardage, S.; Wålinder, M.E.P.; Swerin, A. Superamphiphobic Overhang Structured Coating on a Biobased Material. Appl. Surf. Sci. 2016, 389, 135–143.
  169. de Cademartori, P.H.G.; Stafford, L.; Blanchet, P.; Magalhães, W.L.E.; de Muniz, G.I.B. Enhancing the Water Repellency of Wood Surfaces by Atmospheric Pressure Cold Plasma Deposition of Fluorocarbon Film. RSC Adv. 2017, 7, 29159–29169.
  170. Levasseur, O.; Vlad, M.; Profili, J.; Gherardi, N.; Sarkissian, A.; Stafford, L. Deposition of Fluorocarbon Groups on Wood Surfaces Using the Jet of an Atmospheric-Pressure Dielectric Barrier Discharge. Wood Sci. Technol. 2017, 51, 1339–1352.
  171. Bigan, M.; Mutel, B. Cold Remote Plasma Modification of Wood: Optimization Process Using Experimental Design. Appl. Surf. Sci. 2018, 453, 423–435.
  172. Sohbatzadeh, F.; Shabannejad, A.; Ghasemi, M.; Mahmoudsani, Z. Deposition of Halogen-Free Flame Retardant and Water-Repellent Coatings on Firwood Surfaces Using the New Version of DBD. Prog. Org. Coat. 2021, 151, 106070.
  173. Chen, W.; Zhou, X.; Zhang, X.; Feizbakhshan, M.; Cao, Y.; Shi, S.; Nguyen, T.; Chen, M. Fast Formation of Hydrophobic Coating on Wood Surface via an Energy-Saving Dielectric Barrier Discharges Plasma. Prog. Org. Coat. 2018, 125, 128–136.
  174. Köhler, R.; Sauerbier, P.; Militz, H.; Viöl, W. Atmospheric Pressure Plasma Coating of Wood and MDF with Polyester Powder. Coatings 2017, 7, 171.
  175. Köhler, R.; Sauerbier, P.; Ohms, G.; Viöl, W.; Militz, H. Wood Protection through Plasma Powder Deposition—An Alternative Coating Process. Forests 2019, 10, 898.
  176. Jnido, G.; Ohms, G.; Viöl, W. One-Step Deposition of Polyester/TiO2 Coatings by Atmospheric Pressure Plasma Jet on Wood Surfaces for UV and Moisture Protection. Coatings 2020, 10, 184.
  177. Gascón-Garrido, P.; Mainusch, N.; Militz, H.; Viöl, W.; Mai, C. Copper and Aluminium Deposition by Cold-Plasma Spray on Wood Surfaces: Effects on Natural Weathering Behaviour. Eur. J. Wood Wood Prod. 2017, 75, 315–324.
  178. Jnido, G.; Ohms, G.; Viöl, W. Deposition of Zinc Oxide Coatings on Wood Surfaces Using the Solution Precursor Plasma Spraying Process. Coatings 2021, 11, 183.
  179. Jnido, G.; Ohms, G.; Viöl, W. Deposition of TiO2 Thin Films on Wood Substrate by an Air Atmospheric Pressure Plasma Jet. Coatings 2019, 9, 441.
  180. Kettner, F.; Plaschkies, K.; Gerullis, S.; Pfuch, A.; Küzün, B. Raising the Permanent Adhesion of Coatings on Resinous Wood by APPCVD Promotion. Int. J. Adhes. Adhes. 2020, 102, 102642.
  181. Fernández-Costas, C.; Palanti, S.; Charpentier, J.P.; Sanromán, M.Á.; Moldes, D. A Sustainable Treatment for Wood Preservation: Enzymatic Grafting of Wood Extractives. ACS Sustain. Chem. Eng. 2017, 5, 7557–7567.
  182. Wang, Y.; Tang, Z.; Lu, S.; Zhang, M.; Liu, K.; Xiao, H.; Huang, L.; Chen, L.; Wu, H.; Ni, Y. Superhydrophobic Wood Grafted by Poly(2-(Perfluorooctyl)Ethyl Methacrylate) via ATRP with Self-Cleaning, Abrasion Resistance and Anti-Mold Properties. Holzforschung 2020, 74, 799–809.
  183. Sharma, G.; Kumar, A.; Naushad, M.; Al-Misned, F.A.; El-Serehy, H.A.; Ghfar, A.A.; Rai Sharma, K.; Si, C.; Stadler, F.J. Graft Copolymerization of Acrylonitrile and Ethyl Acrylate onto Pinus Roxburghii Wood Surface Enhanced Physicochemical Properties and Antibacterial Activity. J. Chem. 2020, 2020, 6285354.
  184. Filgueira, D.; Moldes, D.; Fuentealba, C.; García, D.E. Condensed Tannins from Pine Bark: A Novel Wood Surface Modifier Assisted by Laccase. Ind. Crops Prod. 2017, 103, 185–194.
  185. Song, L.; Zhang, X.F.; Wang, Z.; Bai, Y.; Feng, Y.; Yao, J. Metal-Ion Induced Surface Modification for Durable Hydrophobic Wood. Adv. Mater. Interfaces 2020, 7, 2001166.
  186. Pouzet, M.; Dubois, M.; Charlet, K.; Béakou, A. From Hydrophilic to Hydrophobic Wood Using Direct Fluorination: A Localized Treatment. Comptes Rendus Chim. 2018, 21, 800–807.
  187. Pouzet, M.; Dubois, M.; Charlet, K.; Béakou, A.; Leban, J.M.; Baba, M. Fluorination Renders the Wood Surface Hydrophobic without Any Loss of Physical and Mechanical Properties. Ind. Crops Prod. 2019, 133, 133–141.
  188. Pouzet, M.; Dubois, M.; Charlet, K.; Petit, E.; Béakou, A.; Dupont, C. Fluorination/Torrefaction Combination to Further Improve the Hydrophobicity of Wood. Macromol. Chem. Phys. 2019, 220, 1900041.
  189. Gabrič, M.V.; Boncina, T.; Humar, M.; Pohleven, F. Laccase Treatment of Norway Spruce Wood Surface Improves Resistance and Copper Fixation of Treated Wood. Drewno 2016, 59, 19–34.
  190. Kotlyarova, I.A.; Stepina, I.V. Decrease in Swelling Capacity of Pine Wood Modified with Aminoborates. IOP Conf. Ser. Mater. Sci. Eng. 2018, 463, 022007.
  191. James, R.M.S.; Md Tahir, P.; Hua, L.S.; Abdullah, U.H.; Uyup, M.K.A.; Mohd Yusof, N.; Johari, I. Finishing Performance of Acacia mangium Wood Surface-Treated with Methanol. J. Adhes. 2020, 1–20.
  192. Barkai, H.; Elabed, S.; Sadiki, M.; Boutahari, S.; Mounyr, B.; Omar, E.F. The Effect of Cellulase Treatment Time on the Cedar Wood Surface Physicochemical Properties. Am. J. Adv. Sci. Res. 2016, 3, 296–304.
  193. Barkai, H.; Soumya, E.; Sadiki, M.; Mounyr, B.; Ibnsouda, K.S. Impact of Enzymatic Treatment on Wood Surface Free Energy: Contact Angle Analysis. J. Adhes. Sci. Technol. 2017, 31, 726–734.
  194. Lin, W.; Huang, Y.; Li, J.; Liu, Z.; Yang, W.; Li, R.; Chen, H.; Zhang, X. Preparation of Highly Hydrophobic and Anti-Fouling Wood Using Poly(Methylhydrogen)Siloxane. Cellulose 2018, 25, 7341–7353.
  195. Papadopoulos, A.N.; Foti, D.; Kyzas, G.Z. Sorption Behavior of Water Vapor of Wood Treated by Chitosan Polymer. Eur. J. Wood Wood Prod. 2020, 78, 483–491.
  196. Reinprecht, L.; Vidholdová, Z. The Impact of a CO2 Laser on the Adhesion and Mold Resistance of a Synthetic Polymer Layer on a Wood Surface. Forests 2021, 12, 242.
  197. Vidholdová, Z.; Reinprecht, L.; Igaz, R. The Impact of Laser Surface Modification of Beech Wood on Its Color and Occurrence of Molds. BioResources 2017, 12, 4177–4186.
  198. Kúdela, J.; Reinprecht, L.; Vidholdová, Z.; Andrejko, M. Surface Properties of Beech Wood Modified by CO2 Laser. Acta Fac. Xylologiae Zvolen 2019, 61, 5–18.
  199. Kymäläinen, M.; Hautamäki, S.; Lillqvist, K.; Segerholm, K.; Rautkari, L. Surface Modification of Solid Wood by Charring. J. Mater. Sci. 2017, 52, 6111–6119.
  200. Kymäläinen, M.; Turunen, H.; Cermák, P.; Hautamäki, S.; Rautkari, L. Sorption-Related Characteristics of Surface Charred Spruce Wood. Materials 2018, 11, 2083.
  201. Čermák, P.; Dejmal, A.; Paschová, Z.; Kymäläinen, M.; Dömény, J.; Brabec, M.; Hess, D.; Rautkari, L. One-Sided Surface Charring of Beech Wood. J. Mater. Sci. 2019, 54, 9497–9506.
  202. Akcay, C.; Karal Saygin, İ.; Tascioglu, C. Decay Resistance of Carbonized Wood Surfaces. Düzce Univ. J. Sci. Technol. 2020, 8, 746–753.
  203. Triquet, J.; Blanchet, P.; Landry, V. Chemical Surface Densification of Hardwood through Lateral Monomer Impregnation and in Situ Electron Beam Polymerization, Part I: Density Profile and Surface Hardness of Three Hardwood Species. J. Mater. Sci. 2021, 56, 11309–11323.
  204. Wu, J.; Fan, Q.; Wang, Q.; Guo, Q.; Tu, D.; Chen, C.; Xiao, Y.; Ou, R. Improved Performance of Poplar Wood by an Environmentally-Friendly Process Combining Surface Impregnation of a Reactive Waterborne Acrylic Resin and Unilateral Surface Densification. J. Clean. Prod. 2020, 261, 121022.
  205. Han, L. Reduction of Set-Recovery of Surface-Densified Scots Pine by Furfuryl Alcohol. Master’s Thesis, Luleå University of Technology, Luleå, Sweden, 2019.
  206. Neyses, B.; Rautkari, L.; Yamamoto, A.; Sandberg, D. Pre-Treatment with Sodium Silicate, Sodium Hydroxide, Ionic Liquids or Methacrylate Resin to Reduce the Set-Recovery and Increase the Hardness of Surface-Densified Scots Pine. iForest 2017, 10, 857–864.
  207. Lafond, C.; Blanchet, P.; Landry, V.; Galimard, P.; Ménard, S. The Effects of Acrylate Impregnation of Black Spruce Timber as Connectors Strength. BioResources 2016, 11, 1753–1764.
  208. Dagher, R.; Landry, V.; Stevanovic, T. Contribution to Understanding the Color Development on Wood Surfaces Treated with Iron Salts by a Combination of Analytical Methods. J. Wood Chem. Technol. 2020, 40, 223–234.
  209. Harandi, D.; González-Benito, J.; Olmos, D. Consolidation of Fir Wood by Poly(Vinyl Butyral-Co-Vinyl Alcohol-Co-Vinyl Acetate) Treatment: Study of Surface and Mechanical Characteristics. Polymers 2020, 12, 1039.
  210. Kumar, A.; Ryparová, P.; Škapin, A.S.; Humar, M.; Pavlič, M.; Tywoniak, J.; Hajek, P.; Žigon, J.; Petrič, M. Influence of Surface Modification of Wood with Octadecyltrichlorosilane on Its Dimensional Stability and Resistance against Coniophora Puteana and Molds. Cellulose 2016, 23, 3249–3263.
  211. Kumar, A.; Richter, J.; Tywoniak, J.; Hajek, P.; Adamopoulos, S.; Šegedin, U.; Petric, M. Surface Modification of Norway Spruce Wood by Octadecyltrichlorosilane (OTS) Nanosol by Dipping and Water Vapour Diffusion Properties of the OTS-Modified Wood. Holzforschung 2017, 72, 45–56.
  212. He, S.; Wu, W.; Zhang, M.; Qu, H.; Xu, J. Synergistic Effect of Silica Sol and K2CO3 on Flame-Retardant and Thermal Properties of Wood. J. Therm. Anal. Calorim. 2017, 128, 825–832.
  213. Zhu, X.; Liu, Y.; Dong, N.; Li, Z. Fabrication and Characterization of Reversible Thermochromic Wood Veneers. Sci. Rep. 2017, 7, 16933.
  214. Pokrovskaya, E. Fire-Protection of Wooden Structures by Modification in a Thin Surface Layer. In Proceedings of the MATEC Web of Conferences 251: Integration, Partnership and Innovation in Construction Science and Education (IPICSE-2018), Moscow, Russia, 14–16 November 2018; pp. 1–5.
  215. Kim, I.; Karlsson, O.; Myronycheva, O.; Jones, D.; Sandberg, D. Methacrylic Resin for Protection of Wood from Discoloration by Mould Growth and Weathering. BioResources 2020, 15, 7018–7033.
  216. Hassan, B.; Soumya, E.; Moulay, S.; Mounyr, B.; Hajar, M.; Koraichi, I.S. Evaluation of Hydrophobic-Hydrophilic Properties and Anti-Adhesive Potential of the Treated Cedar Wood by Two Essential Oil Components Against Bioadhesion of Penicillium Expansum Spores. J. Appl. Sci. 2016, 16, 372–379.
  217. Yves, K.G.; Chen, T.; Aladejana, J.T.; Wu, Z.; Xie, Y. Preparation, Test, and Analysis of a Novel Aluminosilicate-Based Antimildew Agent Applied on the Microporous Structure of Wood. ACS Omega 2020, 5, 8784–8793.
  218. Qian, J.; He, Z.; Li, J.; Wang, Z.; Qu, L.; Yi, S. Effect of Wax and Dimethyl Silicone Oil Pretreatment on Wood Hygroscopicity, Chemical Components, and Dimensional Stability. BioResources 2019, 13, 6265–6279.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Video Production Service
Feedback