Abstract: In order to make normal PI films with some new characteristics to be used as microelectronic materials, such as excellent adhesive properties and low electric constants, a novel kind of PI composite film containing different contents on each surface was prepared with chemical surface-modification, from poly(imidesiloxane) copolymer and polyimide. First, poly(imidesiloxane) copolymer was synthesized from 4,4'-oxydianiline(ODA), α,ω-aminopropylpoly(dimethylsiloxane)(PDMS) and 3,3',4,4'-biphenyltetracarboxylic dianhydride(s-BPDA). Then, a THF solution of the copolyamide acid and a DMAc solution of the polyamide acid were mixed thoroughly and doctored on a glass plate dried at RT, and then with thermal imidization to get the composite film. All characterization results from X-ray photoelectron spectroscopy(XPS) and contact angle measurements show that the PDMS has segregated to the air surface and predominated in it. Moreover, the composite film has nearly the same excellent thermal properties and mechanical properties as the normal PI films.

Key words: Poly(imidesiloxane), Composite film, Surface modification