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A novel resin, poly(dimethylsilylene-ethynylene-phenoxyphenoxyphenylene-ethynylene), was synthesized from 1,4-bis( p-ethynylphenoxy)benzene and dimethyldichlorosilane through Grignard reaction. The structures of the monomer and the resin were characterized by elemental analysis, Fourier transform infrared, proton nuclear magnetic resonance, electron ionization-mass spectrometry and gel permeation chromatography. The thermal behaviour of the resin was examined by differential scanning calorimetry. The cured resin exhibits excellent dielectric property, high glass transition temperature, good mechanical properties and high thermal stability. The flexural strength and impact strength of the cured resin were 55.0 MPa and 10.5 KJ m−2, respectively. The degradation temperature at 5% weight loss of the cured resin arrived at 549°C in nitrogen.

Perfluorosulfonate ionomer (PFSI) membranes are widely used in electrochemical applications such as fuel cells, chlor-alkali cells, and actuators/sensors. In this work, the surface crystallization of a solution-cast PFSI membrane is quantitatively characterized for the first time by synchrotron grazing incidence X-ray diffraction (GIXRD) and small angle X-ray scattering (GISAXS). A crystallite-rich skin is observed on the PFSI membrane surface, which is 4 nm thick, possesses a crystallinity which is 40% higher than the bulk, with the crystallites aligned parallel to the membrane surface. An intermediate layer exists between the skin and the bulk. The discovery of a crystallite-rich skin may help to explain the surface properties of PFSI membranes, and facilitate an understanding of the transport properties across the membrane interface.

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