Proton conducting nanocomposite membranes consisting of poly(vinylidene fluoride-co-chlorotrifluoroethy-lene)-graft-poly(styrene sulfonic acid), i.e., P(VDF-co-CTFE)-g-PSSA graft copolymer and sulfonated silica and were prepared using a sol-gel reaction and subsequent oxidation of a silica precursor, i.e., (3-mercaptopropyl) trimethoxysilane (MPTMS). The successful formation of amorphous phase nanocomposite membranes was confirmed via FT-IR and wide-angle X-ray scattering. All membranes were semi-transparent and mechanically strong, as characterized by a universal tensile machine. Transmission electron microscopy and small-angle X-ray scattering analysis revealed that silica 5-10 nm in size were homogeneously dispersed in the matrix at up to 5 wt.% of MPTMS. At higher concentrations, the silica grew to more than 50 nm in size, which disrupted the microphase-separated structure of the graft copolymer. As a result, both proton conductivity (0.12 S/cm at 25 °C) and single cell performance (1.0 W/cm 2 at 75 °C) were maximal at 5 wt.% MPTMS.
Bibliographical noteFunding Information:
This work was supported by the Ministry of Knowledge Economy through the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) (20104010100500) and the New and Renewable Energy R&D program (2009T100100606). This work was also supported by a National Research Foundation (NRF) grant funded by the Korean government (MEST) through the Korea Center for Artificial Photosynthesis (KCAP) located in Sogang University (NRF-2009-C1AAA001-2009-0093879).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Electrical and Electronic Engineering