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Heo JW, An L, Kim MS, Youn DH, Kim YS. Preparation and characterization of zwitterion-substituted lignin/Nafion composite membranes. Int J Biol Macromol 2023; 253:127421. [PMID: 37838126 DOI: 10.1016/j.ijbiomac.2023.127421] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 10/10/2023] [Accepted: 10/10/2023] [Indexed: 10/16/2023]
Abstract
In this study, a novel zwitterion-substituted lignin (ZL) containing amino and sulfonic acid groups was synthesized, and ZL/Nafion composite membranes were fabricated as proton exchange membranes. Kraft lignin was modified using an aminosilane and 1,3-propanesultone via a continuous grafting reaction to provide zwitterionic moieties. Chemical structural analyses confirmed the successful introduction of the zwitterion moiety into lignin. In particular, the surface charge of ZL is positive in an acidic medium and negative in a basic medium, suggesting that ZL is a zwitterionic material. ZL was incorporated into a Nafion membrane to enhance its ion exchange capacity, thermal stability, and hydrophilicity. The proton conductivity of ZL/Nafion 0.5 %, 151.0 mS/cm, was 55.3 % higher than that of unmodified ML (methanol-soluble lignin)/Nafion 0.5 % (97.2 mS/cm), indicating that the zwitterion moiety of ZL enhances the proton transport ability. In addition, oxidative stability evaluation confirmed that ZL/Nafion 2 % was chemically more durable than pure Nafion. This confirmed that using lignin as a membrane additive yielded positive results in terms of chemical durability and oxidation stability in Nafion. Therefore, ZL is expected to be utilized as a multifunctional additive and exhibits the potential for fuel cell applications.
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Affiliation(s)
- Ji Won Heo
- Department of Paper Science & Engineering, College of Forest and Environmental Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Liangliang An
- Faculty of Chemical and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Min Soo Kim
- Department of Paper Science & Engineering, College of Forest and Environmental Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Duck Hyun Youn
- Department of Chemical Engineering, Department of Integrative Engineering for Hydrogen Safety, Kangwon National University, Chuncheon 24341, Republic of Korea.
| | - Yong Sik Kim
- Department of Paper Science & Engineering, College of Forest and Environmental Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Gao X, Yamamoto K, Hirai T, Uchiyama T, Ohta N, Takao N, Matsumoto M, Imai H, Sugawara S, Shinohara K, Uchimoto Y. Morphology Changes in Perfluorosulfonated Ionomer from Thickness and Thermal Treatment Conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3871-3878. [PMID: 32168455 DOI: 10.1021/acs.langmuir.9b03564] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The morphological changes of Nafion thin films with thicknesses from 10 to 200 nm on Pt substrate with various annealing histories (unannealed to 240 °C) were systematically investigated using grazing incidence small-angle X-ray scattering (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS). The results revealed that the hydrophilic ionic domain and hydrophobic backbone in Nafion thin films changed significantly when the annealing treatment exceeded the cluster transition temperature, which decreased proton conductivity, due to the constrained hydrophilic/hydrophobic phase separation, and increased the crystalline-rich domain. This research contributed to the understanding of ionomer thermal stability in the catalyst layer, which is subjected to thermal annealing during the hot-pressing process.
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Affiliation(s)
- Xiao Gao
- Graduated School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kentaro Yamamoto
- Graduated School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Tomoyasu Hirai
- Department of Applied Chemistry, Osaka Institute of Technology, 5-16-1 Ohmiya, Asahi-ku, Osaka, 535-8585, Japan
| | - Tomoki Uchiyama
- Graduated School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Noboru Ohta
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo-gun, Hyogo 679-5198, Japan
| | - Naoki Takao
- Nissan Analysis and Research Center, 1, Natsushimacho, Yokosuka-shi, Kanagawa 237-8523, Japan
| | - Masashi Matsumoto
- Nissan Analysis and Research Center, 1, Natsushimacho, Yokosuka-shi, Kanagawa 237-8523, Japan
| | - Hideto Imai
- Nissan Analysis and Research Center, 1, Natsushimacho, Yokosuka-shi, Kanagawa 237-8523, Japan
| | - Seiho Sugawara
- Fuel Cell Cutting-Edge Research Center Technology Research Association, 2-3-26, Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Kazuhiko Shinohara
- Fuel Cell Cutting-Edge Research Center Technology Research Association, 2-3-26, Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Yoshiharu Uchimoto
- Graduated School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501, Japan
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Abstract
In this comprehensive review, recent progress and developments on perfluorinated sulfonic-acid (PFSA) membranes have been summarized on many key topics. Although quite well investigated for decades, PFSA ionomers' complex behavior, along with their key role in many emerging technologies, have presented significant scientific challenges but also helped create a unique cross-disciplinary research field to overcome such challenges. Research and progress on PFSAs, especially when considered with their applications, are at the forefront of bridging electrochemistry and polymer (physics), which have also opened up development of state-of-the-art in situ characterization techniques as well as multiphysics computation models. Topics reviewed stem from correlating the various physical (e.g., mechanical) and transport properties with morphology and structure across time and length scales. In addition, topics of recent interest such as structure/transport correlations and modeling, composite PFSA membranes, degradation phenomena, and PFSA thin films are presented. Throughout, the impact of PFSA chemistry and side-chain is also discussed to present a broader perspective.
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Affiliation(s)
- Ahmet Kusoglu
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B, Berkeley, California 94720, United States
| | - Adam Z Weber
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B, Berkeley, California 94720, United States
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