Progress on highly proton-conductive polymer thin films with organized structure and molecularly oriented structure

References

• Grubb WT, Niedrach LW. Batteries with solid ion‐exchange membrane electrolytes: II. Low‐temperature hydrogen‐oxygen fuel cells. J Electrochem Soc. 1960;107(2):131–135.
   Web of Science ®Google Scholar
• Grubb WT, inventor; General Electric Co., assignee. Fuel Cell. US, GB, FR, DE patent 2913511. 1959 1955 Jun 29.
   Google Scholar
• Hsu WY, Gierke TD. Ion transport and clustering in nafion perfluorinated membranes. J Membr Sci. 1983;13(3):307–326.
   Web of Science ®Google Scholar
• Rikukawa M, Sanui K. Proton-conducting polymer electrolyte membranes based on hydrocarbon polymers. Prog Polym Sci. 2000;25(10):1463–1502.
   Web of Science ®Google Scholar
• Kreuer KD. On the development of proton conducting polymer membranes for hydrogen and methanol fuel cells. J Membr Sci. 2001;185(1):29–39.
   Web of Science ®Google Scholar
• Hickner MA, Ghassemi H, Kim YS, et al. Alternative polymer systems for proton exchange membranes (PEMs). Chem Rev. 2004;104(10):4587–4611.
   PubMed Web of Science ®Google Scholar
• Yang Y, Holdcroft S. Synthetic strategies for controlling the morphology of proton conducting polymer membranes. Fuel Cells. 2005;5(2):171–186.
   Web of Science ®Google Scholar
• Chang Y, Brunello GF, Fuller J, et al. Aromatic ionomers with highly acidic sulfonate groups: acidity, hydration, and proton conductivity. Macromolecules. 2011;44(21):8458–8469.
   Web of Science ®Google Scholar
• Allen FI, Comolli LR, Kusoglu A, et al. Morphology of hydrated as-cast nafion revealed through cryo electron tomography. ACS Macro Lett. 2015;4(1):1–5.
   PubMed Web of Science ®Google Scholar
• Ruokolainen J, Makinen R, Torkkeli M, et al. Switching supramolecular polymeric materials with multiple length scales. Science. 1998;280(5363):557–560.
   PubMed Web of Science ®Google Scholar
• Park MJ, Balsara NP. Anisotropic proton conduction in aligned block copolymer electrolyte membranes at equilibrium with humid air. Macromolecules. 2010;43(1):292–298.
   Web of Science ®Google Scholar
• Chen Y, Thorn M, Christensen S, et al. Enhancement of anhydrous proton transport by supramolecular nanochannels in comb polymers. Nat Chem. 2010;2(6):503–508.
   PubMed Web of Science ®Google Scholar
• Sato T, Hayasaka Y, Mitsuishi M, et al. High proton conductivity in the molecular interlayer of a polymer nanosheet multilayer film. Langmuir. 2015;31(18):5174–5180.
   PubMed Web of Science ®Google Scholar
• Sato T, Tsukamoto M, Yamamoto S, et al. Acid-group-content-dependent proton conductivity mechanisms at the interlayer of poly(N-dodecylacrylamide-co-acrylic acid) copolymer multilayer nanosheet films. Langmuir. 2017;33(45):12897–12902.
   PubMed Web of Science ®Google Scholar
• Matsui J, Miyata H, Hanaoka Y, et al. Layered ultrathin proton conductive film based on polymer nanosheet assembly. ACS Appl Mater Inter. 2011;3(5):1394–1397.
   PubMed Web of Science ®Google Scholar
• Tsukamoto M, Ebata K, Sakiyama H, et al. Biomimetic polyelectrolytes based on polymer nanosheet films and their proton conduction mechanism. Langmuir. 2019;35(9):3302–3307.
   PubMed Web of Science ®Google Scholar
• Trigg EB, Gaines TW, Maréchal M, et al. Self-assembled highly ordered acid layers in precisely sulfonated polyethylene produce efficient proton transport. Nat Mater. 2018;17:725–731.
   PubMed Web of Science ®Google Scholar
• Trigg EB, Winey KI. Nanoscale layers in polymers to promote ion transport. Mol Syst Des Eng. 2019;4(2):252–262.
   Web of Science ®Google Scholar
• Nagao Y, Iguchi F, Sata N, et al. Preparation of new proton conducting oligomers for investigation of inorganic-organic interface effects. The 2nd Summer Seminar on Nanoionics; 2006 Sep 11-13; Hyogo, Japan 2006.
   Google Scholar
• Nagao Y, Iguchi F, Sata N, et al. New proton-conductive oligomers for investigation of inorganic-organic interface effects. The 5th Petite Workshop on Defect Chemical Nature of Adanced Materials; 2006 Nov 17-19; Kyoto, Japan 2006.
   Google Scholar
• Nagao Y. Proton-conductivity enhancement in polymer thin films. Langmuir. 2017;33(44):12547–12558.
   PubMed Web of Science ®Google Scholar
• Nagao Y. Proton-conductive polymer thin films by molecular orientation and organized structure. Kobunshi Ronbunshu (In Japanese). 2018;75(6):576–587.
   Web of Science ®Google Scholar
• Nagao Y, Naito N, Iguchi F, et al. Synthesis of oligomeric poly (1, 2-propanediamine)-alt-(oxalic acid) and anomalous proton conductivities of the thin films. Solid State Ion. 2009;180(6–8):589–591.
   Web of Science ®Google Scholar
• Nagao Y, Naito N, Iguchi F, et al. Proton conductivity of oligomeric poly (1,2-Propanediamine)-Alt-(Oxalic Acid) thin films on Al2O3 substrates. e-J Surf Sci Nanotechnol. 2009;7:530–532.
   Google Scholar
• Nagao Y. Substrate dependence of the proton transport and oriented structure in oligo(1,2-propanediamine)-alt-(oxalic acid) thin films. Chem Lett. 2013;42(5):468–470.
   Web of Science ®Google Scholar
• Tamura T, Kawakami H. Aligned electrospun nanofiber composite membranes for fuel cell electrolytes. Nano Lett. 2010;10(4):1324–1328.
   PubMed Web of Science ®Google Scholar
• Mauritz KA, Moore RB. State of understanding of Nafion. Chem Rev. 2004;104(10):4535–4585.
   PubMed Web of Science ®Google Scholar
• Kusoglu A, Weber AZ. New insights into perfluorinated sulfonic-acid lonomers. Chem Rev. 2017;117(3):987–1104.
   PubMed Web of Science ®Google Scholar
• Dong B, Gwee L, Cruz DS-D, et al. Super proton conductive high-purity nafion nanofibers. Nano Lett. 2010;10(9):3785–3790.
   PubMed Web of Science ®Google Scholar
• Liu X, Li Y, Xue J, et al. Magnetic field alignment of stable proton-conducting channels in an electrolyte membrane. Nat Commun. 2019;10(1):842.
   PubMedGoogle Scholar
• Kato T, Yoshio M, Ichikawa T, et al. Transport of ions and electrons in nanostructured liquid crystals. Nat Rev Mater. 2017;2:17001.
   Web of Science ®Google Scholar
• Karan K. Interesting facets of surface, interfacial, and bulk characteristics of perfluorinated ionomer films. Langmuir. 2019;35(42):13489–13520.
   PubMed Web of Science ®Google Scholar
• Siroma Z, Kakitsubo R, Fujiwara N, et al. Depression of proton conductivity in recast Nafion (R) film measured on flat substrate. J Power Sources. 2009;189(2):994–998.
   Web of Science ®Google Scholar
• Nagao Y. Highly oriented sulfonic acid groups in a nafion thin film on si substrate. J Phys Chem C. 2013;117(7):3294–3297.
   Web of Science ®Google Scholar
• Nagao Y. Proton transport property of nafion thin films on MgO(100) with anisotropic molecular structure. e-J Surf Sci Nanotechnol. 2012;10:114–116.
   Google Scholar
• Nagao Y, Enta A, Suwansoontorn A, et al. Proton conductivity and oriented structure of nafion thin films on the au-deposited surface and MgO substrate. ECS Trans. 2018;88(1):249–258.
   Google Scholar
• Ono Y, Interfacial Structure NY. Proton conductivity of nafion at the Pt-deposited surface. Langmuir. 2016;32(1):352–358.
   PubMed Web of Science ®Google Scholar
• Hasegawa T. A novel measurement technique of pure out-of-plane vibrational modes in thin films on a nonmetallic material with no polarizer. J Phys Chem B. 2002;106(16):4112–4115.
   Web of Science ®Google Scholar
• Hasegawa T. Advanced multiple-angle incidence resolution spectrometry for thin-layer analysis on a low-refractive-index substrate. Anal Chem. 2007;79(12):4385–4389.
   PubMed Web of Science ®Google Scholar
• Shioya N, Tomita K, Shimoaka T, et al. Second generation of multiple-angle incidence resolution spectrometry. J Phys Chem A. 2019;123(32):7177–7183.
   PubMed Web of Science ®Google Scholar
• Shioya N, Shimoaka T, Eda K, et al. A new schematic for poly(3-alkylthiophene) in an amorphous film studied using a novel structural index in infrared spectroscopy. Phys Chem Chem Phys. 2015;17(20):13472–13479.
   PubMed Web of Science ®Google Scholar
• Abiko K, Kato Y. Analysis of the molecular orientation of poly(3-hexylthiophene) on silicon treated with silane coupling agents, by infrared p-polarized multiple-angle incidence resolution spectrometry. Chem Lett. 2018;47(3):332–335.
   Web of Science ®Google Scholar
• Hada M, Shioya N, Shimoaka T, et al. Comprehensive understanding of structure-controlling factors of a zinc tetraphenylporphyrin thin film using pMAIRS and GIXD techniques. Chem: Eur J. 2016;22(46):16539–16546.
   PubMed Web of Science ®Google Scholar
• Shioya N, Murdey R, Nakao K, et al. Alternative face-on thin film structure of pentacene. Sci Rep. 2019;9(1):579.
   PubMedGoogle Scholar
• Zhang R, Murata M, Aharen T, et al. Synthesis of a distinct water dimer inside fullerene C70. Nat Chem. 2016;8(5):435–441.
   PubMed Web of Science ®Google Scholar
• Nakamura T, Shioya N, Shimoaka T, et al. Molecular orientation change in naphthalene diimide thin films induced by removal of thermally cleavable substituents. Chem Mater. 2019;31(5):1729–1737.
   Web of Science ®Google Scholar
• Nakamura T, Shioya N, Hasegawa T, et al. Phthalimide-based transparent electron-transport materials with oriented-amorphous structures: preparation from solution-processed precursor films. ChemPlusChem. 2019;84(9):1396–1404.
   PubMed Web of Science ®Google Scholar
• Truong MA, Lee J, Nakamura T, et al. Influence of alkoxy chain length on the properties of two-dimensionally expanded azulene-core-based hole-transporting materials for efficient perovskite solar cells. Chem: Eur J. 2019;25(27):6741–6752.
   PubMed Web of Science ®Google Scholar
• Wang C, Hosomi T, Nagashima K, et al. Rational method of monitoring molecular transformations on metal-oxide nanowire surfaces. Nano Lett. 2019;19(4):2443–2449.
   PubMed Web of Science ®Google Scholar
• Sakakibara K, Nishiumi K, Shimoaka T, et al. pMAIRS analysis on chain-end functionalization of densely grafted, concentrated polymer brushes. Macromolecules. 2019;52(17):6673–6682.
   Web of Science ®Google Scholar
• Ishige R, Tanaka K, Ando S. In situ analysis of chain orientation behavior in thin film aromatic polyimides by variable temperature pMAIRS during thermal imidization. Macromol Chem Phys. 2018;219(3):1700370.
   Web of Science ®Google Scholar
• Nagao Y. A study on the plasma-treated surfaces of MgO(100) and quartz substrates by infrared multiple-angle incidence resolution spectrometry. e-J Surf Sci Nanotechnol. 2012;10:229–233.
   Google Scholar
• Krishnan K, Yamada T, Iwatsuki H, et al. Influence of confined polymer structure on proton transport property in sulfonated polyimide thin films. Electrochemistry. 2014;82(10):865–869.
   Web of Science ®Google Scholar
• Nagao Y, Krishnan K, Goto R, et al. Effect of casting solvent on interfacial molecular structure and proton transport characteristics of sulfonated polyimide thin films. Anal Sci. 2017;33(1):35–39.
   PubMed Web of Science ®Google Scholar
• Gruger A, Regis A, Schmatko T, et al. Nanostructure of nafion membranes at different states of hydration an IR and raman study. Vib Spectrosc. 2001;26(2):215–225.
   Web of Science ®Google Scholar
• Kendrick I, Kumari D, Yakaboski A, et al. Elucidating the ionomer-electrified metal interface. J Am Chem Soc. 2010;132(49):17611–17616.
   PubMed Web of Science ®Google Scholar
• Zimudzi TJ, Hickner MA. Signal enhanced FTIR analysis of alignment in NAFION thin films at SiO2 and Au interfaces. ACS Macro Lett. 2016;5(1):83–87.
   PubMed Web of Science ®Google Scholar
• Davis EM, Stafford CM, Page KA. Elucidating water transport mechanisms in nafion thin films. ACS Macro Lett. 2014;3(10):1029–1035.
   PubMed Web of Science ®Google Scholar
• Zeng JB, Jean DI, Ji CX, et al. In situ surface-enhanced raman spectroscopic studies of nafion adsorption on Au and Pt electrodes. Langmuir. 2012;28(1):957–964.
   PubMed Web of Science ®Google Scholar
• Malevich D, Zamlynny V, Sun SG, et al. In situ infrared reflection absorption spectroscopy studies of the interaction of nafion (R) with the Pt electrode surface. Z Phys Chem. 2003;217(5):513–525.
   Web of Science ®Google Scholar
• Korzeniewski C, Snow DE, Basnayake R. Transmission infrared spectroscopy as a probe of nafion film structure: analysis of spectral regions fundamental to understanding hydration effects. Appl Spectrosc. 2006;60(6):599–604.
   PubMed Web of Science ®Google Scholar
• Ozhukil Kollath V, Liang Y, Mayer FD, et al. Model-based analyses of confined polymer electrolyte nanothin films experimentally probed by polarized ATR–FTIR spectroscopy. J Phys Chem C. 2018;122(17):9578–9585.
   Web of Science ®Google Scholar
• Yagi I, Inokuma K, Kimijima K, et al. Molecular structure of buried perfluorosulfonated ionomer/Pt interface probed by vibrational sum frequency generation spectroscopy. J Phys Chem C. 2014;118(45):26182–26190.
   Web of Science ®Google Scholar
• Kushner DI, Kusoglu A, Podraza NJ, et al. Substrate-dependent molecular and nanostructural orientation of nafion thin films. Adv Funct Mater. 2019;29(37):1902699.
   Web of Science ®Google Scholar
• Sone Y, Ekdunge P, Simonsson D. Proton conductivity of nafion 117 as measured by a four-electrode AC impedance method. J Electrochem Soc. 1996;143(4):1254–1259.
   Web of Science ®Google Scholar
• Guo Y, Ono Y, Nagao Y. Modification for uniform surface of nafion ultrathin film deposited by inkjet printing. Langmuir. 2015;31(37):10137–10144.
   PubMed Web of Science ®Google Scholar
• Paul DK, Fraser A, Pearce J, et al. Understanding the ionomer structure and the proton conduction mechanism in PEFC catalyst layer: adsorbed nafion on model substrate. ECS Trans. 2011;41(1):1393–1406.
   Google Scholar
• Modestino MA, Paul DK, Dishari S, et al. Self-assembly and transport limitations in confined nafion films. Macromolecules. 2013;46(3):867–873.
   Web of Science ®Google Scholar
• Shim HK, Paul DK, Karan K. Resolving the contradiction between anomalously high water uptake and low conductivity of nanothin nafion films on SiO2 substrate. Macromolecules. 2015;48(22):8394–8397.
   Web of Science ®Google Scholar
• Siroma Z, Ioroi T, Fujiwara N, et al. Proton conductivity along interface in thin cast film of Nafion (R). Electrochem Commun. 2002;4(2):143–145.
   Web of Science ®Google Scholar
• Tesfaye M, Kushner DI, Kusoglu A. Interplay between swelling kinetics and nanostructure in perfluorosulfonic acid thin-films: role of hygrothermal aging. ACS Appl Polym Mater. 2019;1(4):631–635.
   Web of Science ®Google Scholar
• Shrivastava U, Suetsugu K, Nagano S, et al. Cross-correlated humidity dependent structural evolution of nafion thin film confined on platinum substrate. Soft Matter. 2020. DOI:https://doi.org/10.1039/C9SM01731C
   Google Scholar
• Choi P, Jalani NH, Thermodynamics DR. Proton transport in nafion: II. proton diffusion mechanisms and conductivity. J Electrochem Soc. 2005;152(3):E123–E130.
   Web of Science ®Google Scholar
• Shrivastava UN, Fritzsche H, Interfacial KK. Bulk water in ultrathin films of nafion, 3M PFSA, and 3M PFIA ionomers on a polycrystalline platinum surface. Macromolecules. 2018;51(23):9839–9849.
   Web of Science ®Google Scholar
• Ogata Y, Abe T, Yonemori S, et al. Impact of the solid interface on proton conductivity in nafion thin films. Langmuir. 2018;34(50):15483–15489.
   PubMed Web of Science ®Google Scholar
• Su GM, Cordova IA, Yandrasits MA, et al. Chemical and morphological origins of improved ion conductivity in perfluoro ionene chain extended ionomers. J Am Chem Soc. 2019;141(34):13547–13561.
   PubMed Web of Science ®Google Scholar
• Takeuchi K, Kuo A-T, Hirai T, et al. Hydrogen permeation in hydrated perfluorosulfonic acid polymer membranes: effect of polymer crystallinity and equivalent weight. J Phys Chem C. 2019;123(33):20628–20638.
   Web of Science ®Google Scholar
• Dudenas PJ, Kusoglu A. Evolution of ionomer morphology from dispersion to film: an in situ X-ray study. Macromolecules. 2019;52(20):7779–7785.
   Web of Science ®Google Scholar
• Pramounmat N, Loney CN, Kim C, et al. Controlling the distribution of perfluorinated sulfonic acid ionomer with elastin-like polypeptide. ACS Appl Mater Interfaces. 2019;11(46):43649–43658.
   PubMed Web of Science ®Google Scholar
• Kawamoto T, Aoki M, Kimura T, et al. Sublayered structures of hydrated nafion® thin film formed by casting on Pt substrate analyzed by X-ray absorption spectroscopy under ambient conditions and neutron reflectometry at temperature of 80°C and relative humidity of 30–80%. Electrochemistry. 2019 ;87(5):270–275.
   Web of Science ®Google Scholar
• Liu H, Epting WK, Litster S. Gas transport resistance in polymer electrolyte thin films on oxygen reduction reaction catalysts. Langmuir. 2015;31(36):9853–9858.
   PubMed Web of Science ®Google Scholar
• Kudo K, Jinnouchi R, Morimoto Y. Humidity and temperature dependences of oxygen transport resistance of nafion thin film on platinum electrode. Electrochim Acta. 2016;209:682–690.
   Web of Science ®Google Scholar
• Wang C, Cheng X, Yan X, et al. Respective influence of ionomer content on local and bulk oxygen transport resistance in the catalyst layer of PEMFCs with low Pt loading. J Electrochem Soc. 2019;166(4):F239–F245.
   Web of Science ®Google Scholar
• Nagao Y, Ando M, Maekawa H, et al. Synthesis and proton transport property of poly(aspartic acid) thin film on MgO(100) substrate. ECS Trans. 2009;16(51):401–406.
   Google Scholar
• Nagao Y, Iguchi F, Sata N, et al. Synthesis and proton transport property of poly(aspartic acid) thin film on SiO2 substrate. Solid State Ion. 2010;181(3–4):206–209.
   Web of Science ®Google Scholar
• Nagao Y, Kubo T. Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates. Appl Surf Sci. 2014;323:19–24.
   Web of Science ®Google Scholar
• Nagao Y, Matsui J. Anisotropic proton conductivity of poly(aspartic acid) thin films. Mater Today Proc. 2019;17:953–958.
   Google Scholar
• Nagao Y, Matsui J, Abe T, et al. Enhancement of proton transport in an oriented polypeptide thin film. Langmuir. 2013;29(23):6798–6804.
   PubMed Web of Science ®Google Scholar
• Hiramatsu H. Secondary structure analysis of proteins using infrared absorption spectroscopy. PSSJ Arch. 2009;2:e054.
   Google Scholar
• Faure S, Cornet N, Gebel G, et al., editors. Sulfonated polyimides as novel proton exchange membranes for H2/O2 fuel cells. New Mater. Fuel Cell Mod. Battery Syst. II: Proc. of the 2nd Int. Symp; 1997: Ecole Polytechnique de Montreal; Montréal, Québec, Canada.
   Google Scholar
• Vallejo E, Pourcelly G, Gavach C, et al. Sulfonated polyimides as proton conductor exchange membranes. Physicochemical properties and separation H+/Mz+ by electrodialysis comparison with a perfluorosulfonic membrane. J Membr Sci. 1999;160(1):127–137.
   Web of Science ®Google Scholar
• Fang JH, Guo XX, Harada S, et al. Novel sulfonated polyimides as polyelectrolytes for fuel cell application. 1. Synthesis, proton conductivity, and water stability of polyimides from 4,4 ‘-diaminodiphenyl ether-2,2 ‘-disulfonic acid. Macromolecules. 2002;35(24):9022–9028.
   Web of Science ®Google Scholar
• Miyatake K, Asano N, Watanabe M. Synthesis and properties of novel sulfonated polyimides containing 1,5-naphthylene moieties. J Polym Sci Pol Chem. 2003;41(24):3901–3907.
   Web of Science ®Google Scholar
• Woo Y, Oh SY, Kang YS, et al. Synthesis and characterization of sulfonated polyimide membranes for direct methanol fuel cell. J Membr Sci. 2003;220(1–2):31–45.
   Web of Science ®Google Scholar
• Peckham TJ, Schmeisser J, Rodgers M, et al. Main-chain, statistically sulfonated proton exchange membranes: the relationships of acid concentration and proton mobility to water content and their effect upon proton conductivity. J Mater Chem. 2007;17(30):3255–3268.
   Google Scholar
• Krishnan K, Iwatsuki H, Hara M, et al. Proton conductivity enhancement in oriented, sulfonated polyimide thin films. J Mater Chem A. 2014;2(19):6895–6903.
   Web of Science ®Google Scholar
• Wegner G. Ultrathin films of polymers: architecture, characterization and properties. Thin Solid Films. 1992;216(1):105–116.
   Web of Science ®Google Scholar
• Collings JP, Hird M. Introduction to liquid crystals: chemistry and physics. London: CRC Press; 1997.
   Google Scholar
• Nagao Y, Ohno K, Tsuyuki S, et al. Effect of molecular orientation to proton conductivity in sulfonated polyimides with bent backbones. Mol Cryst Liq Cryst. 2019;686(1):84–91.
   Web of Science ®Google Scholar
• Krishnan K, Iwatsuki H, Hara M, et al. Influence of molecular weight on molecular ordering and proton transport in organized sulfonated polyimide thin films. J Phys Chem C. 2015;119(38):21767–21774.
   Web of Science ®Google Scholar
• Ono Y, Goto R, Hara M, et al. High Proton Conduction of Organized Sulfonated Polyimide Thin Films with Planar and Bent Backbones. Macromolecules. 2018;51(9):3351–3359.
   Web of Science ®Google Scholar
• Wakita J, Jin S, Shin TJ, et al. Analysis of molecular aggregation structures of fully aromatic and semialiphatic polyimide films with synchrotron grazing incidence wide-angle X-ray scattering. Macromolecules. 2010;43(4):1930–1941.
   Web of Science ®Google Scholar
• Takakura K, Ono Y, Suetsugu K, et al. Lyotropic ordering for high proton conductivity in sulfonated semialiphatic polyimide thin films. Polym J. 2019;51(1):31–39.
   Web of Science ®Google Scholar
• Concellón A, Hernández-Ainsa S, Barberá J, et al. Proton conductive ionic liquid crystalline poly(ethyleneimine) polymers functionalized with oxadiazole. RSC Adv. 2018;8(66):37700–37706.
   PubMed Web of Science ®Google Scholar
• Mulder D-J, Liang T, Xu Y, et al. Proton conductive cationic nanoporous polymers based on smectic liquid crystal hydrogen-bonded heterodimers. J Mater Chem C. 2018;6(18):5018–5024.
   Web of Science ®Google Scholar
• Ono A, Ohno H, Kato T, et al. Design of 3D continuous proton conduction pathway by controlling co-organization behavior of gemini amphiphilic zwitterions and acids. Solid State Ion. 2018;317:39–45.
   Web of Science ®Google Scholar
• Concellón A, Liang T, Schenning APHJ, et al. Proton-conductive materials formed by coumarin photocrosslinked ionic liquid crystal dendrimers. J Mater Chem C. 2018;6(5):1000–1007.
   PubMed Web of Science ®Google Scholar
• Kobayashi T, Li Y-X, Ono A, et al. Gyroid structured aqua-sheets with sub-nanometer thickness enabling 3D fast proton relay conduction. Chem Sci. 2019;10(25):6245–6253.
   PubMed Web of Science ®Google Scholar
• Champagne P-L, Ester D, Polan D, et al. Amphiphilic cyclodextrin-based liquid crystals for proton conduction. J Am Chem Soc. 2019;141(23):9217–9224.
   PubMed Web of Science ®Google Scholar
• Kumar KRS, Gupta M, Sakamoto T, et al. Thermotropic columnar liquid crystals based on wedge-shaped phenylphosphonic acids. Bull Chem Soc Jpn. 2019;92(9):1450–1452.
   Web of Science ®Google Scholar
• Ueda S, Kagimoto J, Ichikawa T, et al. Anisotropic proton-conductive materials formed by the self-organization of phosphonium-type zwitterions. Adv Mater. 2011;23(27):3071–3074.
   PubMed Web of Science ®Google Scholar
• Ichikawa T, Kato T, Ohno H. 3D continuous water nanosheet as a gyroid minimal surface formed by bicontinuous cubic liquid-crystalline zwitterions. J Am Chem Soc. 2012;134(28):11354–11357.
   PubMed Web of Science ®Google Scholar
• Yabu H, Matsui J, Hara M, et al. Proton conductivities of lamellae-forming bioinspired block copolymer thin films containing silver nanoparticles. Langmuir. 2016;32(37):9484–9491.
   PubMed Web of Science ®Google Scholar
• Yabu H, Nagano S, Nagao Y. Core-shell cylinder (CSC) nanotemplates comprising mussel-inspired catechol-containing triblock copolymers for silver nanoparticle arrays and ion conductive channels. RSC Adv. 2018;8(19):10627–10632.
   PubMed Web of Science ®Google Scholar
• Kim O, Kim K, Choi UH, et al. Tuning anhydrous proton conduction in single-ion polymers by crystalline ion channels. Nat Commun. 2018;9(1):5029.
   PubMedGoogle Scholar
• Liang T, van Kuringen HPC, Mulder DJ, et al. Anisotropic dye adsorption and anhydrous proton conductivity in smectic liquid crystal networks: the role of cross-link density, order, and orientation. ACS Appl Mater Interfaces. 2017;9(40):35218–35225.
   PubMed Web of Science ®Google Scholar
• Kumar A, Pisula W, Sieber C, et al. Anhydrous proton conduction in self-assembled and disassembled ionic molecules. J Mater Chem A. 2018;6(14):6074–6084.
   Web of Science ®Google Scholar