E-Polymers: Comparison
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E-polymers, also known as conducting polymers, are a class of materials that exhibit both electrical conductivity and the mechanical properties of polymers. The use of e-polymer materials in daily life is becoming increasingly widespread, especially in the field of biology. Since the manufacturing cost of e-polymer implants is relatively low and e-polymers also react, causing different chemical molecules to attach to the surface of the implant, they are more compatible with the surrounding environment of the body. Some e-polymers are biodegradable in the body. If used for temporary implants, the advantage of these polymers is that they can gradually degrade in the body after performing their functions, thereby reducing the possibility of any long-term complications. Polymers and their composite materials can be designed to have inherent tensile properties while maintaining their high performance, making them favorable candidates for the next generation of skin-inspired electronic materials.

  • e-polymers
  • stretchability
  • bio-interface
  • 3D structure
  • sensor
  • energy harvesting

1. Synthesis and Design of E-Polymers

In our daily lives, we encounter a wide variety of e-polymers, some of which are natural and some of which are synthetic [47][1]. Sufficient flexibility and biocompatibility compared to inorganic materials, as well as a range of electron transport, chemical functionality, and tailored mechanical and optical properties, are all advantages that make e-polymers very attractive [48][2]. E-polymers utilize specialized chemical substances and composite materials for biological applications [49,50][3][4]. The synthetic-based electronic polymers encompass conducting hydrogels and ionogels, electrochemical transistors, and topological supramolecular networks. The synthesis of e-polymers involves the polymerization of monomers with conjugated structures to form long-chain polymers that exhibit electronic and optoelectronic properties.
E-polymers based on artificial synthesis are those that are synthesized from monomers or building blocks that are not found in nature. Unlike polymers based on biomolecules, which use natural biopolymers as precursors, these polymers are designed and synthesized using synthetic chemistry techniques [51,52][5][6]. One approach to synthesizing polymers is through step-growth polymerization, which involves gradually forming a polymer chain through reacting reactive groups at the ends of the growing chain with functional groups on monomers [53,54][7][8]. This technique can create various polymers with different properties, such as polycarbonates, polyesters, and polyamides. Another approach is through chain-growth polymerization, which involves initiating a polymerization reaction at a reactive site on a monomer, followed by adding more monomers to the growing chain [55,56][9][10]. In addition to these traditional polymerization methods, researchers are also exploring new strategies for the synthesis of polymers, such as click chemistry, which involves the selective reaction of two functional groups to form a covalent bond. Click reactions can be used to create complex polymer structures with precise control over their size and shape [55,57,58][9][11][12]. Polymer semiconductors have shown unique development advantages in the development of human-integrated electronic products due to their solution processability and mechanical flexibility. However, many of the functional characteristics required in this application field are transferred to conjugated polymers, which are combined with effective charge transfer properties. In a study, Li et al. developed a “click-to-polymer” (CLIP) synthesis strategy that utilizes click reactions to attach different types of functional units to pre-synthesized conjugated polymer precursors [59][13]. It has been proven that the functionalized polymer of the method can still maintain good carrier mobility. The functional properties of conjugated polymers can be greatly enriched by using this synthetic method.
The most commonly used materials for conventional planar electronic devices are inorganic, but the brittle and mechanical properties of inorganic materials are unsuitable for applications in the biological field [60][14]. Extensive research has attempted to find alternative materials that bypass mechanical limitations without sacrificing functionality or performance. Materials ranging from single-crystal silicon nanofilms, nanowires, and nanobelts to conjugated small-molecule organic polycrystalline films are semiconductor component choices for such thin flexible devices and are valuable for the research and development of flexible devices [61][15]. Scalable bioelectronic devices are based on flexible and conductive organic materials that allow rational interfaces for biocompatible integration with the human body. In a study, Jiang et al. developed a molecular engineering strategy based on topological supramolecular networks that decouple competitive effects from multiple molecular components [62][16]. Under physiological conditions, both high conductivity and crack initiation strain were obtained, exhibiting direct photosensitivity to the cell scale. Further, the stable EMG signals of the octopus were collected, local neuromodulation was conducted, and the specific activities of the organ were conducted through the exemplary brainstem controller.
The basic principle of complementary metal-oxide-semiconductor technology is to utilize the complementary properties of p-type and n-type metal-oxide-semiconductor materials to achieve an efficient operation of circuits [63,64][17][18]. For the construction of CMOS logic circuits and p–n junction devices, n-type semiconductors play a crucial role [65][19]. Among various electronic deficient components, cyanide-functionalized hydrocarbons are emerging to achieve high-performance n-type organic and polymer semiconductors [31][20]. In a study, Li et al. developed a large number of n-type organic semiconductors and polymer semiconductors based on these cyanide functional compositions, which show many suppressed frontier molecular orbitals (FMOs) compared to their non-cyanide analogs [66][21]. The incorporation of cyanide significantly inhibits FMOs in semiconductors, leading to an n-type transport. A series of new electron-deficient components can be generated to build n-type organic and polymer semiconductors, which ultimately manifests itself in enhanced device performance. For further development, integrated design strategies are a feasible way to achieve these goals, thereby promoting the construction of high-performance n-type semiconductors. The synthesis of e-polymers based on artificial synthesis offers a powerful tool for creating new materials with tailored properties and functions, including applications in materials science, electronics, and biomedicine. In a study, Wang et al. presented a fundamentally stretchable polymer transistor array with an unprecedented device density of 347 transistors per square centimeter [67][22]. Consequently, transistor arrays essentially constitute stretchable skin electronics, including active matrices for sensing arrays as well as analog and digital circuit elements.

2. Properties of E-Polymers

E-polymers have many properties and unique electrical and photovoltaic properties that allow them to be used in a variety of applications [67,68,69][22][23][24]. Many e-polymers have high strength and durability, making them ideal for use in products that require durability and robustness. In addition, inherently stretchable semiconductor polymers use molecular structure engineering, such as length and branching of alkyl side chains, molecular weight, and the design of blends containing both rigid and flexible electronic blocks, to make the copolymers stretchable [70,71][25][26]. E-polymers can conduct electricity, which sets them apart from traditional insulating polymers. Depending on the chemical structure, doping, and processing conditions, e-polymers have different conductivity properties ranging from semiconducting behavior to metallic conductivity [72,73,74][27][28][29]. E-polymers can exhibit interesting optical properties, including absorption and emission of light in the visible and near-infrared regions. The energy band gap of an e-polymer can be tuned by changing its chemical structure, thereby controlling the wavelength of the emitted light. E-polymers can transport charge carriers (electrons or holes) through a conjugated backbone. The mobility of charge carriers in e-polymers is influenced by factors such as polymer crystallinity, chain organization, and molecular weight. Efficient charge transport is critical for applications such as organic solar cells, transistors, and conductive coatings. One of the advantages of e-polymers is their flexibility and processability [75,76,77][30][31][32]. They can be made into films, fibers, or coatings by a variety of techniques such as solution casting, spin-coating, printing, or vapor phase deposition. This flexibility allows e-polymers to be integrated into flexible and lightweight devices, opening up possibilities for wearable electronics and flexible displays. E-polymers can undergo redox reactions, meaning they can be oxidized or reduced while maintaining a conjugated structure [78][33]. Compared to traditional inorganic semiconductors, e-polymers typically have good environmental stability. However, their stability can vary depending on factors such as polymer selection, device design, and operating conditions [79][34]. In addition, e-polymers typically have potential environmental advantages over conventional inorganic electronic materials. They can be synthesized from abundant renewable resources, and some polymers are biocompatible [80][35]. Beneficially, e-polymer devices have the potential for low-cost manufacturing processes, thereby reducing the environmental impact of the manufacturing process. These properties of e-polymers make them attractive for a variety of applications, including organic electronics, optoelectronics, sensors, energy conversion and storage, smart textiles, and biomedical devices [81][36].
A growing and widespread concern is the application of e-polymers to bio-interfaces and organisms [82,83][37][38]. There is an imperative demand to synthesize novel and sustainable e-polymers for bio-interface and organism applications that can functionally replace the existing e-polymers or exhibit their properties and advantages. In a study, Kang et al. described a new class of polymeric material crosslinked through rationally designed multistrength hydrogen-bonding interactions [84][39]. A supramolecular polymer film constructed through a mixture of strong and weak crosslinking hydrogen bonds is described. The resulting polymer possesses various mechanical properties required for electronic skin applications, such as stretchability, toughness, and the ability to autonomously self-heal even in water. As this polymer is easy to manipulate, capacitive strain-sensing electronic skins are designed and fabricated to be highly resilient and resistant to vandalism. The exhibits feature an advanced structure, excellent thermo–mechanical properties, higher stability, lower flammability, better processing conditions, and improved appearance. In a study, Li et al. demonstrated stretchable transistor arrays and active matrix circuits with moduli below 10 kPa [85][40]. Due to an improved adaptability to irregular and dynamic surfaces, an ultrasoft device fabricated using a soft sandwich design enables electrophysiological recording of the isolated heart. High adaptability, spatial stability, and minimal impact on ventricular pressure were achieved. Additionally, testing has demonstrated the benefits of inhibiting foreign body reactions for long-term implantation, resulting in superior in vivo biocompatibility. E-polymers have similar electrical and electrochemical properties to traditional semiconductors and metals, thus receiving widespread attention in both basic and practical research [86,87][41][42]. The electrical conductivity of organic radical polymers is much higher than expected, and organic radical polymers have unusual electronic properties [88][43]. Conductivity can be improved in two approaches. On the one hand, this can be accomplished by the synthesis of molecular structures with a relatively large dispersion of π-bonds; the higher the dispersion, the improved conductivity of the conjugated structure. Consequently, improving the intrinsic conductivity of polymers from the perspective of the molecular structure is an optimal solution. In addition, improving production processes and preparing polymer materials with larger molecular weights and more regular structures are also important means to improve their conductivity. On the other hand, the chemical doping of conjugated structures is an effective way to enhance the conductivity of polymer materials by introducing anions (p-type doping) or cations (n-type doping) on the polymer chain through doping methods to reduce energy barriers and facilitate electron migration. The commonly used dopants include iodine, arsenic pentafluoride, antimony hexafluoride, silver perchlorate, etc. After the dopants are saturated, the conductivity of the material will not change [89,90][44][45]. Therefore, it will be important to find suitable doping agents and dope them reasonably with conductive polymers.

References

  1. Miao, J.; Wang, Y.; Liu, J.; Wang, L. Organoboron molecules and polymers for organic solar cell applications. Chem. Soc. Rev. 2022, 51, 153–187.
  2. Osaka, I.; Takimiya, K. Naphthobischalcogenadiazole Conjugated Polymers: Emerging Materials for Organic Electronics. Adv. Mater. 2017, 29, 1605218.
  3. Sailor, M.J.; Klavetter, F.L.; Grubbs, R.H.; Lewis, N.S. Electronic properties of junctions between silicon and organic conducting polymers. Nature 1990, 346, 155–157.
  4. Qiao, Z.; Shen, M.; Xiao, Y.; Zhu, M.; Mignani, S.; Majoral, J.-P.; Shi, X. Organic/inorganic nanohybrids formed using electrospun polymer nanofibers as nanoreactors. Coord. Chem. Rev. 2018, 372, 31–51.
  5. Clothier, G.K.K.; Guimarães, T.R.; Thompson, S.W.; Rho, J.Y.; Perrier, S.; Moad, G.; Zetterlund, P.B. Multiblock copolymer synthesis via RAFT emulsion polymerization. Chem. Soc. Rev. 2023, 52, 3438–3469.
  6. Kim, J.; Lee, K.H.; Lee, J.Y. Extracting Polaron Recombination from Electroluminescence in Organic Light-Emitting Diodes by Artificial Intelligence. Adv. Mater. 2023, 35, 2209953.
  7. Wang, Y.; Liu, Y. Insight into conjugated polymers for organic electrochemical transistors. Trends Chem. 2023, 5, 279–294.
  8. Wang, Z.; Zhang, Y.; Wang, T.; Hao, L.; Lin, E.; Chen, Y.; Cheng, P.; Zhang, Z. Organic flux synthesis of covalent organic frameworks. Chem 2023, 9, 2178–2193.
  9. Liang, S.; Xiao, C.; Xie, C.; Liu, B.; Fang, H.; Li, W. 13% Single-Component Organic Solar Cells based on Double-Cable Conjugated Polymers with Pendent Y-Series Acceptors. Adv. Mater. 2023, 35, 2300629.
  10. Wang, Y.; He, Q.; Wang, Z.; Zhang, S.; Li, C.; Wang, Z.; Park, Y.-L.; Cai, S. Liquid Crystal Elastomer Based Dexterous Artificial Motor Unit. Adv. Mater. 2023, 35, 2211283.
  11. Li, J.; Qian, Y.; Li, W.; Yu, S.; Ke, Y.; Qian, H.; Lin, Y.; Hou, C.; Shyue, J.; Zhou, J.; et al. Polymeric Memristor Based Artificial Synapses with Ultra-Wide Operating Temperature. Adv. Mater. 2023, 35, 2209728.
  12. Liu, Q.; Sun, Q.; Shen, J.; Li, H.; Zhang, Y.; Chen, W.; Yu, S.; Li, X.; Chen, Y. Emerging tetrapyrrole porous organic polymers for chemosensing applications. Coord. Chem. Rev. 2023, 482, 215078.
  13. Li, N.; Dai, Y.; Li, Y.; Dai, S.; Strzalka, J.; Su, Q.; De Oliveira, N.; Zhang, Q.; St. Onge, P.B.J.; Rondeau-Gagné, S.; et al. A universal and facile approach for building multifunctional conjugated polymers for human-integrated electronics. Matter 2021, 4, 3015–3029.
  14. Wu, J.; Wang, N.; Xie, Y.-R.; Liu, H.; Huang, X.; Cong, X.; Chen, H.-Y.; Ma, J.; Liu, F.; Zhao, H.; et al. Polymer-like Inorganic Double Helical van der Waals Semiconductor. Nano Lett. 2022, 22, 9054–9061.
  15. Mahenderkar, N.K.; Chen, Q.; Liu, Y.-C.; Duchild, A.R.; Hofheins, S.; Chason, E.; Switzer, J.A. Epitaxial lift-off of electrodeposited single-crystal gold foils for flexible electronics. Science 2017, 355, 1203–1206.
  16. Jiang, Y.; Zhang, Z.; Wang, Y.-X.; Li, D.; Coen, C.-T.; Hwaun, E.; Chen, G.; Wu, H.-C.; Zhong, D.; Niu, S.; et al. Topological supramolecular network enabled high-conductivity, stretchable organic bioelectronics. Science 2022, 375, 1411–1417.
  17. Feng, K.; Shan, W.; Wang, J.; Lee, J.; Yang, W.; Wu, W.; Wang, Y.; Kim, B.J.; Guo, X.; Guo, H. Cyano-Functionalized n-Type Polymer with High Electron Mobility for High-Performance Organic Electrochemical Transistors. Adv. Mater. 2022, 34, 2201340.
  18. Zhang, Y.; Wang, Y.; Gao, C.; Ni, Z.; Zhang, X.; Hu, W.; Dong, H. Recent advances in n-type and ambipolar organic semiconductors and their multi-functional applications. Chem. Soc. Rev. 2023, 52, 1331–1381.
  19. Shen, T.; Li, W.; Zhao, Y.; Wang, Y.; Liu, Y. A Hybrid Acceptor-Modulation Strategy: Fluorinated Triple-Acceptor Architecture for Significant Enhancement of Electron Transport in High-Performance Unipolar n-Type Organic Transistors. Adv. Mater. 2023, 35, 2210093.
  20. Sun, H.; Guo, X.; Facchetti, A. High-Performance n-Type Polymer Semiconductors: Applications, Recent Development, and Challenges. Chem 2020, 6, 1310–1326.
  21. Li, Y.; Huang, E.; Guo, X.; Feng, K. Cyano-functionalized organic and polymeric semiconductors for high-performance n-type organic electronic devices. Mater. Chem. Front. 2023, 7, 3803–3819.
  22. Wang, S.; Xu, J.; Wang, W.; Wang, G.-J.N.; Rastak, R.; Molina-Lopez, F.; Chung, J.W.; Niu, S.; Feig, V.R.; Lopez, J.; et al. Skin electronics from scalable fabrication of an intrinsically stretchable transistor array. Nature 2018, 555, 83–88.
  23. Ochs, J.; Pagnacco, C.A.; Barroso-Bujans, F. Macrocyclic polymers: Synthesis, purification, properties and applications. Prog. Polym. Sci. 2022, 134, 101606.
  24. Kim, J.H.; Kang, D.W.; Yun, H.; Kang, M.; Singh, N.; Kim, J.S.; Hong, C.S. Post-synthetic modifications in porous organic polymers for biomedical and related applications. Chem. Soc. Rev. 2022, 51, 43–56.
  25. Korshak, Y.V.; Medvedeva, T.V.; Ovchinnikov, A.A.; Spector, V.N. Organic polymer ferromagnet. Nature 1987, 326, 370–372.
  26. Lin, Z.; Kabe, R.; Nishimura, N.; Jinnai, K.; Adachi, C. Organic Long-Persistent Luminescence from a Flexible and Transparent Doped Polymer. Adv. Mater. 2018, 30, 1803713.
  27. Luo, D.; Li, M.; Ma, Q.; Wen, G.; Dou, H.; Ren, B.; Liu, Y.; Wang, X.; Shui, L.; Chen, Z. Porous organic polymers for Li-chemistry-based batteries: Functionalities and characterization studies. Chem. Soc. Rev. 2022, 51, 2917–2938.
  28. Liu, W.; Zhang, C.; Alessandri, R.; Diroll, B.T.; Li, Y.; Liang, H.; Fan, X.; Wang, K.; Cho, H.; Liu, Y.; et al. High-efficiency stretchable light-emitting polymers from thermally activated delayed fluorescence. Nat. Mater. 2023, 22, 737–745.
  29. Kohlman, R.S.; Joo, J.; Min, Y.G.; MacDiarmid, A.G.; Epstein, A.J. Crossover in Electrical Frequency Response through an Insulator-Metal Transition. Phys. Rev. Lett. 1996, 77, 2766–2769.
  30. Ning, H.; Jiang, Q.; Han, P.; Lin, M.; Zhang, G.; Chen, J.; Chen, H.; Zeng, S.; Gao, J.; Liu, J.; et al. Manipulating the solubility properties of polymer donors for high-performance layer-by-layer processed organic solar cells. Energy Environ. Sci. 2021, 14, 5919–5928.
  31. Noro, S.-I.; Kitagawa, S.; Akutagawa, T.; Nakamura, T. Coordination polymers constructed from transition metal ions and organic N-containing heterocyclic ligands: Crystal structures and microporous properties. Prog. Polym. Sci. 2009, 34, 240–279.
  32. Yao, N.; Wang, J.; Chen, Z.; Bian, Q.; Xia, Y.; Zhang, R.; Zhang, J.; Qin, L.; Zhu, H.; Zhang, Y.; et al. Efficient Charge Transport Enables High Efficiency in Dilute Donor Organic Solar Cells. J. Phys. Chem. Lett. 2021, 12, 5039–5044.
  33. Gao, W.; Yu, C. Wearable and Implantable Devices for Healthcare. Adv. Healthc. Mater. 2021, 10, 2101548.
  34. Tao, K.; Makam, P.; Aizen, R.; Gazit, E. Self-assembling peptide semiconductors. Science 2017, 358, aam9756.
  35. Ratcliff, E.L.; Shallcross, R.C.; Armstrong, N.R. Introduction: Electronic Materials. Chem. Rev. 2016, 116, 12821–12822.
  36. Gumyusenge, A. Organic Iono-Electronics, a New Front for Semiconducting Polymers to Shine. Acc. Mater. Res. 2022, 3, 669–671.
  37. Zhao, F.; Shi, Y.; Pan, L.; Yu, G. Multifunctional Nanostructured Conductive Polymer Gels: Synthesis, Properties, and Applications. Acc. Chem. Res. 2017, 50, 1734–1743.
  38. Zhao, N.; Yan, L.; Zhao, X.; Chen, X.; Li, A.; Zheng, D.; Zhou, X.; Dai, X.; Xu, F.-J. Versatile Types of Organic/Inorganic Nanohybrids: From Strategic Design to Biomedical Applications. Chem. Rev. 2019, 119, 1666–1762.
  39. Kang, J.; Son, D.; Wang, G.-J.N.; Liu, Y.; Lopez, J.; Kim, Y.; Oh, J.Y.; Katsumata, T.; Mun, J.; Lee, Y.; et al. Tough and Water-Insensitive Self-Healing Elastomer for Robust Electronic Skin. Adv. Mater. 2018, 30, 1706846.
  40. Li, Y.; Li, N.; Liu, W.; Prominski, A.; Kang, S.; Dai, Y.; Liu, Y.; Hu, H.; Wai, S.; Dai, S.; et al. Achieving tissue-level softness on stretchable electronics through a generalizable soft interlayer design. Nat. Commun. 2023, 14, 4488.
  41. Grądzka, E.; Wysocka-Żołopa, M.; Winkler, K. Fullerene-Based Conducting Polymers: n-Dopable Materials for Charge Storage Application. Adv. Energy Mater. 2020, 10, 2001443.
  42. Li, J.; Qiao, J.; Lian, K. Hydroxide ion conducting polymer electrolytes and their applications in solid supercapacitors: A review. Energy Storage Mater. 2019, 24, 6–21.
  43. Lutkenhaus, J. A radical advance for conducting polymers. Science 2018, 359, 1334–1335.
  44. Liu, X.; Zheng, W.; Kumar, R.; Kumar, M.; Zhang, J. Conducting polymer-based nanostructures for gas sensors. Coord. Chem. Rev. 2022, 462, 214517.
  45. Le, T.-H.; Kim, Y.; Yoon, H. Electrical and Electrochemical Properties of Conducting Polymers. Polymers 2017, 9, 150.
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