Bifunctional TiO2 nanoparticles with hygroscopic and proton-conductive properties were synthesized by grafting proton-conducting polymer, i.e. poly(styrene sulfonic acid) (PSSA) from TiO2 nanoparitlces via surface-initiated atom transfer radical polymerization (ATRP). These bifunctional TiO2-PSSA nanoparticles were blended with poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(styrene sulfonic acid), i.e. P(VDF-co-CTFE)-g-PSSA to give proton-conducting membranes for high temperature fuel cells. FT-IR, UV-visible spectroscopy and X-ray diffraction (XRD) results revealed bifunctional properties of TiO2-PSSA nanoparticles due to successful grafting of PSSA chains. Ion exchange capacity (IEC) of P(VDF-co-CTFE)-g-PSSA/TiO2-PSSA membranes was not significantly changed irrespective of TiO2-PSSA concentrations, representing almost fixed SO3- concentration in the membranes. In contrast, water uptake and proton conductivity of membranes continuously increased with increasing TiO2-PSSA concentrations, presumably due to hygroscopic, soft conducting property of nanoparticles. The results of thermal gravimetric analysis (TGA) also showed that all the membranes were stable at least up to 280 °C.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation (NRF) grant funded by the Korea government (MEST) through the Pioneer Research Center Program (2008-05103) and the Korea Center for Artificial Photosynthesis (KCAP) located in Sogang University (NRF-2009-C1AAA001-2009-0093879). This work was also supported by New & Renewable Energy R&D program (2009T100100606) under the Ministry of Knowledge Economy, Republic of Korea.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Condensed Matter Physics
- Energy Engineering and Power Technology