Proton conducting crosslinked membranes by polymer blending of triblock copolymer and poly(vinyl alcohol)

Do Kyoung Lee, Jung Tae Park, Jin Kyu Choi, Dong Kyu Roh, Jung Hyun Lee, Yong Gun Shul, Jong Hak Kim

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Proton conducting crosslinked membranes were prepared using polymer blends of polystyrene-b-poly(hydroxyethyl acrylate)-b-poly(styrene sulfonic acid) (PS-b-PHEA-b-PSSA) and poly(vinyl alcohol) (PVA). PS-b-PHEA-b-PSSA triblock copolymer at 28:21:51 wt% was synthesized sequentially using atom transfer radical polymerization (ATRP). FT-IR spectroscopy showed that after thermal (120 °C, 2 h) and chemical (sulfosuccinic acid, SA) treatments of the membranes, the middle PHEA block of the triblock copolymer was crosslinked with PVA through an esterification reaction between the -OH group of the membrane and the -COOH group of SA. The ion exchange capacity (IEC) decreased from 1.56 to 0.61 meq/g with increasing amount of PVA. Therefore, the proton conductivity at room temperature decreased from 0.044 to 0.018 S/cm. However, the introduction of PVA resulted in a decrease in water uptake from 87.0 to 44.3%, providing good mechanical properties applicable to the membrane electrode assembly (MEA) of fuel cells. Transmission electron microscopy (TEM) showed that the membrane was microphase-separated with a nanometer range with good connectivity of the SO3H ionic aggregates. The power density of a single H 2/O2 fuel cell system using the membrane with 50 wt% PVA was 230 mW/cm2 at 70 °C with a relative humidity of 100%. Therrnogravimetric analysis (TGA) also showed a decrease in the thermal stability of the membranes with increasing PVA concentration.

Original languageEnglish
Pages (from-to)549-554
Number of pages6
JournalMacromolecular Research
Volume16
Issue number6
DOIs
Publication statusPublished - 2008 Aug

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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