{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:55:58Z","timestamp":1785426958751,"version":"3.56.0"},"reference-count":36,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,5,25]],"date-time":"2026-05-25T00:00:00Z","timestamp":1779667200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Trade, Industry and Resource","award":["RS-2025-25457767"],"award-info":[{"award-number":["RS-2025-25457767"]}]},{"DOI":"10.13039\/501100013128","name":"Korea Technology and Information Promotion Agency for SMEs","doi-asserted-by":"publisher","award":["RS-2025-25434560"],"award-info":[{"award-number":["RS-2025-25434560"]}],"id":[{"id":"10.13039\/501100013128","id-type":"DOI","asserted-by":"publisher"}]},{"award":["RS-2025-25434560"],"award-info":[{"award-number":["RS-2025-25434560"]}],"id":[{"id":"https:\/\/ror.org\/02kxx1z36","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>This study reports the intermediate-temperature proton exchange membrane (IT-PEM) based on an oligomeric vinyl sulfonic acid (OVS)-infiltrated crosslinked porous polybenzimidazole (cp-PBI) framework. The cp-PBI membrane, fabricated via ZIF-8-templated porosity and covalent crosslinking, provides a mechanically robust and chemically stable host matrix that enables high uptake and uniform distribution of OVS throughout the membrane bulk. In situ oligomerization of vinyl sulfonic acid yields a wax-like OVS ionomer with high proton density and reduced mobility, effectively suppressing ionomer leaching while maintaining efficient proton transport under anhydrous conditions. The resulting membrane exhibits high proton conductivity of 8.4 \u00d7 10\u22123 S cm\u22121 at room temperature and 2.6 \u00d7 10\u22122 S cm\u22121 at 110 \u00b0C without any external humidification. Compared to dense PBI and conventional phosphoric acid (PA)-doped systems, the composite membrane demonstrates significantly enhanced ionomer retention, with only 2.3 wt% loss under compressive conditions and improved stability under humid environments. These results highlight the synergistic effect of a porous crosslinked host and viscous oligomeric ionomer, providing a promising strategy for designing stable, high-performance IT-PEMs.<\/jats:p>","DOI":"10.3390\/polym18111298","type":"journal-article","created":{"date-parts":[[2026,5,25]],"date-time":"2026-05-25T14:10:22Z","timestamp":1779718222000},"page":"1298","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Confinement of Oligomeric Vinyl Sulfonic Acid Within Crosslinked Porous Polybenzimidazole for Intermediate-Temperature Proton Exchange Membranes"],"prefix":"10.3390","volume":"18","author":[{"given":"Hongbin","family":"Na","sequence":"first","affiliation":[{"name":"Department of Chemical and Biochemical Engineering, Dongguk University, Seoul 04620, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7654-224X","authenticated-orcid":false,"given":"Sung-Kon","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biochemical Engineering, Dongguk University, Seoul 04620, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1720","DOI":"10.1016\/j.rser.2006.01.005","article-title":"Applications of proton exchange membrane fuel cell systems","volume":"11","author":"Wee","year":"2007","journal-title":"Renew. 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