Characterization and properties of hybrid composites prepared from poly(vinylidene fluoride–tetrafluoroethylene) and SiO2

Organic–inorganic hybrids were prepared using poly(vinylidene fluoride–tetrafluoroethylene) (P(VDF–TFE)) and tetraethoxysilane (TEOS) via a sol–gel process, and their crystallization and mechanical properties including the morphological features, were investigated. brid films were transparent at TEOS contents up to 20 wt%. However, 30 wt% TEOS hybrid was less transparent due to formation of microvoids rather than pure polymer film. Crystallinity of P(VDF–TFE) in the hybrids increased with increasing TEOS content. This indicated that SiO2 played the role of nucleating agent in the polymer crystallization. The crystal structure of P(VDF–TFE) in the hybrids was found to be β-phase according to X-ray diffraction measurements. No aggregation of SiO2 networks in the hybrids was observed in small angle X-ray scattering measurements. brid films, as well as pure P(VDF–TFE) film, showed clear yielding phenomena in stress–strain relation. The yield strength, yield strain, and tensile modulus of the hybrids increased with increasing TEOS content up to 20 wt%, but decreased abruptly at 30 wt% TEOS. It is interesting that the breaking elongation of the samples was the highest at 10 wt% TEOS, two times higher than that of pure P(VDF–TFE) film. Consequently, the transparent hybrid films could be obtained without any loss in either crystallinity of P(VDF–TFE) or mechanical properties.