Novel Nafion ORMOSIL Hybrids via In Situ Sol-Gel Reactions .1. Probe of ORMOSIL Phase Nanostructures by Infrared Spectroscopy

Document Type

Article

Publication Date

12-1-1995

Department

Polymers and High Performance Materials

Abstract

Novel [polymer]/[organically modified silicon oxide (ORIMOSIL)] hybrids were formulated via sol-gel reactions of mixtures of tetraethoxysilane (TEOS) and diethoxydimethylsilane (DEDMS) in the nanophase-separated morphology of perfluorosulfonic acid (PFSA) films. Molecular structures of ORMOSIL phases were investigated by FT-IR spectroscopy and the spectra compared with those of corresponding bulk ORMOSILs. Spectra are similar for PFSA in situ and bulk ORMOSILs, suggesting that short-range molecular structures in the two states are in fact comparable. Spectral trends with ORMOSIL composition suggest that similar D, Q sequence distributions exist for the two systems. There is evidence of co-condensation between Q and D units within the PFSA, as well as in the bulk ORMOSILs. As DEDMS:TEOS increases, ORMOSIL structures in both in situ and bulk states are increasingly more linear. It appears that a spectrum of energetic environment, or polarity, in the clusters of perfluorosulfonate ionomers can be tailored by adjusting the ratio of Si-OH and Si-CH3 groups in ORMOSIL nanophases.

Publication Title

Chemistry of Materials

Volume

7

Issue

12

First Page

2259

Last Page

2268

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