Synthesis and characterisation of silica hybrids based on poly(ε-caprolactone-b-perfluoropolyether-b-ε-caprolactone)

Poly(ε-caprolactone-b-perfluoropolyether-b-ε-caprolactone) (PCL–PFPE–PCL) triblock copolymers having hydroxy end groups were readily functionalised with triethoxysilane end groups by reactions with 3-isocyanatopropyltriethoxysilane. Organic–inorganic hybrids were prepared by using the sol–gel process in the presence of tetraethoxysilane and hydroxy or triethoxysilane terminated PCL–PFPE–PCL. Fully transparent hybrid materials with high content of organic matter were obtained only in the case of alkoxysilane functionalised copolymers. For such systems the PCL–PFPE–PCL copolymer was so intimately mixed with the inorganic network to prevent crystallisation of the PCL segments. The progress of the sol–gel reaction was limited by the early vetrification of the reactive system, while the interpenetration of the organic phase was enhanced by curing the samples at 100 °C.