A method of fabricating a structure comprising the steps of: providing an electrical conductor; providing a layer of a flexible insulating material on the electrical conductor, the material comprising: a first organo-alkoxide 1RxSi(O1R′)4-x and a second organo-alkoxide 2RxSi(O2R′)4-x, where 1R is a non-hydrolysable organic moiety thermally stable to a temperature of at least 150° C., 2R is a non-hydrolysable organic moiety containing a functional group that can react with another like functional group to form an organic polymer, 1R′ and 2R′ are alkyl radicals and x is an integer from 0 to 3; and an inorganic filler material.