Proton conducting grafted/crosslinked membranes prepared from poly(vinylidene fluoride-co-chlorotrifluoroethylene) copolymer

• Published in: Polymers for advanced technologies Vol. 22; no. 10; pp. 1434 - 1441
• Main Authors: Seo, Jin Ah, Kim, Yong Woo, Roh, Dong Kyu, Shul, Yong Gun, Kim, Jong Hak
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.10.2011
• Subjects: atom transfer radical polymerization (ATRP); Chains (polymeric); Copolymers; Crosslinking; Graft copolymers; Membranes; polymer electrolyte membrane; Polymerization; Polystyrene resins; proton conductivity; Radicals
• ISSN: 1042-7147; 1099-1581; 1099-1581
• DOI: 10.1002/pat.1629

Poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) (P(VDF‐co‐CTFE)) backbone was grafted with crosslinkable chains of poly(hydroxyl ethyl acrylate) (PHEA) and proton conducting chains of poly(styrene sulfonic acid) (PSSA) to produce amphiphilic P(VDF‐co‐CTFE)‐g‐P(HEA‐co‐SSA) graft copolymer via atom transfer radical polymerization (ATRP). Successful synthesis and microphase‐separated structure of the copolymer were confirmed by 1H NMR, FT‐IR spectroscopy, and TEM analysis. Furthermore, this graft copolymer was thermally crosslinked with sulfosuccinic acid (SA) to produce grafted/crosslinked membranes. Ion exchange capacity (IEC) increased continuously with increasing SA contents but the water uptake increased up to 6 wt% of SA concentration, above which it decreased monotonically. The membrane also exhibited a maximum proton conductivity of 0.062 S/cm at 6 wt% of SA concentration, resulting from competitive effect between the increase of ionic groups and the degree of crosslinking. XRD patterns also revealed that the crystalline structures of P(VDF‐co‐CTFE) disrupted upon graft polymerization and crosslinking. These membranes exhibited good thermal stability at least up to 250°C, as revealed by TGA. Copyright © 2009 John Wiley & Sons, Ltd.