Synthesis and characterization of SiO2–PEG hybrid materials

Abstract Sol–gel is a promising technique for the synthesis of organic–inorganic hybrid materials both of class I and II. In materials of class I organic molecules are physically entrapped in an inorganic matrix, while in those of class II organic and inorganic parts are connected by covalent bonds. In this paper a sol–gel procedure to obtain SiO 2 –PEG hybrids of class I, in which PEG is simply mixed at the sol stage, is compared to a sol–gel procedure to obtain SiO 2 –PEG hybrid materials of class II, where a particular sol–gel Si–C precursor is synthesized. XPS analyses showed the different distribution of the organic phase in the SiO 2 matrix and the bond between PEG and SiO 2 for hybrids of class II. The PEG molecule in hybrid of class II showed an enhanced thermal stability up to 350 °C. Doping with a lithium salt was performed on hybrids of class II, and the ionic conductivity was measured.