In situ formation, surface characteristics, and interfacial adhesion of poly(imide siloxane)/tantalum oxide hybrid films

A new poly(imide siloxane)/tantalum oxide (PIS/TaOx) hybrid material has been successfully fabricated through the in situ formation of TaOx within a PIS matrix by sol–gel process. The hybrid thin films are prepared from 4,4-oxydiphthalic anhydride (ODPA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (p-BAPP), α,ω-bis(3-amnopropyl)polydimethyl siloxane (APPS) and p-aminophenyltrimethoxysilane (APTS). The coupling agent APTS is employed to provide covalent bonding between the PIS and the TaOx and to control the block chain length of poly(amic acid siloxane). The effect of TaOx content in the PIS/TaOx hybrid thin films on surface characteristics, thermogravimetric analysis, thermal expansion coefficient, dynamic mechanical properties and the adhesion strength between the PIS/TaOx hybrid films and copper foil are investigated. The presence of TaOx on the hybrid film surface can improve the adhesion strength between the PIS/TaOx hybrid film and copper foil. Furthermore, by incorporating TaOx into the PIS matrix, the PIS/TaOx hybrid film possesses lower thermal expansion coefficient and retains good mechanical and thermal properties as well.