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Topic Review
Sulfonimide-Based Dendrimers
Dendrimers are multifunctional polymer compounds with a tree-like shape and a high branching degree. 
  • 703
  • 25 Feb 2021
Topic Review
Natural and Modified Cyclodextrins as Packaging Additives
Cyclodextrins (CDs) have been used by the pharmaceutical and food industries since the 1970s. Their cavities allow the accommodation of several hydrophobic molecules, leading to the formation of inclusion complexes (ICs) increasing the guest molecules’ stability, allowing their controlled release, enhancing their water solubility and biodisponibility.
  • 703
  • 18 Nov 2021
Topic Review
Self-Healing Mechanism of Hydrogel
The route to achieve self-healing of hydrogels is by noncovalent or reversible dynamic covalent bonding in polymeric materials, and enhancing the conductivity of hydrogels by the addition of conductive fillers, conductive polymers or conductive ions.
  • 698
  • 29 Nov 2021
Topic Review
Application of Polycaprolactone-Based Materials in Nanoformulations
Among the various materials used for the fabrication of nanoparticles, polycaprolactone (PCL) has gained considerable attention due to its biodegradability, biocompatibility, and ease of synthesis.
  • 698
  • 25 Apr 2023
Topic Review
ABC-Type Linear Triblock Terpolymers
This entry aims to cover the most recent advances regarding the synthesis of linear ABC-type triblock terpolymers by RAFT polymerization, as well as their self-assembly properties in aqueous solutions. RAFT polymerization has received extensive attention, as it is a versatile technique, compatible with a great variety of functional monomers and reaction conditions, while providing exceptional and precise control over the final structure, with well-defined side-groups and post-polymerization engineering potential. Linear triblock terpolymers synthesis can lead to very interesting novel ideas, since there are countless combinations of stimuli/non-stimuli and hydrophilic/hydrophobic monomers that someone can use. One of their most interesting features is their ubiquitous ability to self-assemble in different nanostructures depending on their degree of polymerization (DP), block composition, solubilization protocol, internal and external stimuli. 
  • 697
  • 26 May 2021
Topic Review
Graphene Sensors
Graphene is one of the most promising materials for gas-sensor applications.
  • 694
  • 07 Apr 2021
Topic Review
Weak Polyelectrolytes for Nanoarchitectonic Design Tools
The ionization degree, charge density, and conformation of weak polyelectrolytes can be adjusted through adjusting the pH and ionic strength stimuli. Such polymers thus offer a range of reversible interactions, including electrostatic complexation, H-bonding, and hydrophobic interactions, which position weak polyelectrolytes as key nano-units for the design of dynamic systems with precise structures, compositions, and responses to stimuli. From surface platforms to colloids and gels, weak polyelectrolytes have enabled the development of a wide range of functional materials owing to their intrinsic response to stimuli, including solvents, temperature, pH, and salt.
  • 693
  • 30 May 2022
Topic Review
Nitric Oxide for Dermal Application
Nitric oxide (NO•) is a free radical gas, produced in the human body to regulate physiological processes, including skin health. The lack of NO• is known to cause or worsen skin conditions, so an exogenous delivery through NO-donors can compensate its deficiency. This has been incorporated into natural, synthetic and semisynthetic polymeric matrices that have been evaluated for antimicrobial, wound healing and circulatory dermal applications.
  • 689
  • 25 Apr 2021
Topic Review
Hydrogels in Hand Sanitizers
Hand hygiene can be considered a strategic key useful in the containment of infections such as COVID-19 both at home and in communities because it can dramatically reduce the widespread outbreak of infections. 
  • 689
  • 08 May 2021
Topic Review
Directed Assembly of Particle-Polymer Composites
Particle-polymer dispersions are ubiquitous in additive manufacturing (AM), where they are used as inks to create composite materials with applications to wearable sensors, energy storage materials, and actuation elements. It has been observed that directional alignment of the particle phase in the polymer dispersion can imbue the resulting composite material with enhanced mechanical, electrical, thermal or optical properties. 
  • 687
  • 17 Aug 2021
Topic Review
Ionic Hydrogels
Hydrogels are three-dimensional polymer networks with excellent flexibility. Ionic hydrogels have attracted extensive attention in the development of tactile sensors owing to their unique properties, such as ionic conductivity and mechanical properties. These features enable ionic hydrogel-based tactile sensors with exceptional performance in detecting human body movement and identifying external stimuli. Currently, there is a pressing demand for the development of self-powered tactile sensors that integrate ionic conductors and portable power sources into a single device for practical applications.
  • 686
  • 06 Apr 2023
Topic Review
Design of Liquid-Crystalline Elastomeric Fluorescent Force Sensors
Liquid single crystal elastomers (LSCEs) containing carbazole fluorogenic components alter their luminescence when they are stretched along the director direction. The differential luminescent behavior arises from the distinct interaction between the carbazole fluorophores and their local environment before and after the application of the mechanical input. Indeed, the uniaxial deformation of the material, along its anisotropic direction, forces a closer mesogen–fluorophore interaction, which leads to the quenching of the carbazole luminescence. Importantly, this intermolecular interaction is intimately related to the intrinsic order present in the LSCE. As a result, the amount of light emitted by the material in the form of fluorescence diminishes upon deformation. Thus, the application of mechanical stimuli to liquid-crystalline elastomers furnishes to two interconvertible states for the system with distinct optical properties (with either different emission color or fluorescence intensity). The initial state of the material is completely restored once the applied force is removed. In this way, this kind of macromolecular system can transduce mechanical events into detectable and processable optical signals, thus, having great potential as optical force sensors. In this context, the realization of the distinct structural factors that govern the interactions established between the mesogenic and fluorogenic units at the supramolecular level upon deformation is essential for the development of efficient LSCE-based force sensors. In fact, not only the density of carbazole units and their connection to the main polymer backbone, but also the presence of long range molecular order in the system and the type of mesophase exhibited by the LSCE are key factors for the conception of efficient force sensors based on these self-organized polymer networks.
  • 684
  • 20 Dec 2021
Topic Review
Fiber–Hydrogel Composites for Wound Healing
The structural resemblance of fiber–hydrogel composites to natural tissues has been a driving force for the optimization and exploration of these systems in biomedicine. Indeed, the combination of hydrogel-forming techniques and fiber spinning approaches has been crucial in the development of scaffolding systems with improved mechanical strength and medicinal properties.
  • 678
  • 11 Mar 2021
Topic Review
Design and Synthesis of Sidechain Phosphorus-Containing Polyacids
Macromolecules containing acidic fragments in side-groups—polyacids—occupy a special place among synthetic polymers. Properties and applications of polyacids are directly related to the chemical structure of macromolecules: the nature of the acidic groups, polymer backbone, and spacers between the main chain and acidic groups. The chemical nature of the phosphorus results in the diversity of acidic >P(O)OH fragments in sidechain phosphorus-containing polyacids (PCPAs) that can be derivatives of phosphoric or phosphinic acids.
  • 676
  • 13 Feb 2023
Topic Review
Reprocessable Photodeformable Azobenzene Polymers
Photodeformable azobenzene (azo) polymers are a class of smart polymers that can efficiently convert light energy into mechanical power, holding great promise in various photoactuating applications. They are typically of crosslinked polymer networks with highly oriented azo mesogens embedded inside. Upon exposure to the light of appropriate wavelength, they experience dramatic order parameter change following the configuration change of the azo units. This could result in the generation and accumulation of the gradient microscopic photomechanical force in the crosslinked polymer networks, thus leading to their macroscopic deformation. Most of the presently developed photodeformable azo polymers have stable chemically crosslinked networks, which make their reprocessing impossible, thus limiting their large scale applications. To solve this problem, reprocessable photodeformable azo polymers have been recently developed by introducing dynamic crosslinking networks (including physically crosslinked and dynamic covalent bond-crosslinked ones) into their structures. In addition, some uncrosslinked photodeformable azo polymers have also been reported and constitute one special type of reprocessable photodeformable azo polymers, whose photodeformation behaviors are mainly induced by the selective reorientation of the azo moieties (become perpendicular to the polarization direction of the polarized light) under the irradiation of either polarized blue light or interfering polarized light.
  • 675
  • 30 Aug 2021
Topic Review
Biomedical Applications of Antiviral Nanohybrids
The COVID-19 pandemic has driven a global research to uncover novel, effective therapeutical and diagnosis approaches. In addition, control of spread of infection has been targeted through development of preventive tools and measures. In this regard, nanomaterials, particularly, those combining two or even several constituting materials possessing dissimilar physicochemical (or even biological) properties, i.e., nanohybrid materials play a significant role. Nanoparticulate nanohybrids have gained a widespread reputation for prevention of viral crises, thanks to their promising antimicrobial properties as well as their potential to act as a carrier for vaccines. On the other hand, they can perform well as a photo-driven killer for viruses when they release reactive oxygen species (ROS) or photothermally damage the virus membrane. The nanofibers can also play a crucial protective role when integrated into face masks and personal protective equipment, particularly as hybridized with antiviral nanoparticles.
  • 675
  • 16 Sep 2021
Topic Review
SAPO-34 Zeolite Membranes
In the zeolite family, the silicoaluminophosphate (SAPO)-34 zeolite has a unique chemical structure, distinctive pore size, adsorption characteristics, as well as chemical and thermal stability, has attracted much research attention. Increasing global carbon dioxide (CO2) emissions pose a serious environmental threat to humans, animals, plants, and the entire environment.
  • 666
  • 20 Mar 2023
Topic Review
Glass–fibre–reinforced Polymer
Wind barrier structures are usually installed on railway bridges to reduce wind effects on travelling trains for safety considerations. This however adversely transfers wind loads and causes associated aerodynamic effects to the bridge. An innovative concept of wind barriers using glass fibre reinforced polymer (GFRP) composites is proposed in this work with experimental investigations and numerical modelling. This work provides a solution to mitigate the wind and associated aerodynamic loads. With an appropriate design of bending stiffness, the proposed barriers may deform adaptively in strong wind scenarios and let the wind to pass through their deformed shape and therefore transfer less load to the bridge. Wind-tunnel experiments and numerical studies are conducted on the aerodynamic responses of the train-barrier-bridge system under crosswind with various speeds. The influences of barrier height, air-flow speed and location of the train on the aerodynamic responses of the system were clarified. Both reduced-scale and full-scale finite element models were established for the train-barrier-bridge system and the results were validated with the experimental results to further support the research findings.
  • 662
  • 22 Oct 2020
Topic Review
Supercritical Carbon-di-Oxide Technology for Polymeric-Particles
Supercritical carbon dioxide (SC-CO2)  based techniques can be exploited for the formulation of polymeric nanocarriers, limiting the use of toxic organic solvent. The currently approved FDA pharmaceutical polymers like PLA and PLGA particles can be obtained in the micro-and nanometer range by techniques that involve SC-CO2 as solvent (RESS, RESOLV), anti-solvent (SAS, SEDS, SAILA) or extractant (SFEE), depending on the SC-CO2 compatibility with the system materials and the final product.
  • 656
  • 27 Apr 2021
Topic Review
Antimicrobial Peptides and Proteins (AMPs)
Mycotoxins are toxic secondary metabolites produced by filamentous fungi in crops or during storage, transport and processing of food and feed commodities, which pose serious health risks for both humans and animals. The trend of mycotoxin contamination in food and feed has reached alarming levels. Antimicrobial peptides and proteins (AMPs) with antifungal activity are gaining much interest as natural antifungal compounds due to their properties such as structure diversity and function, antifungal spectrum, mechanism of action, high stability and the availability of biotechnological production methods. 
  • 651
  • 14 Jan 2022
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