Polyimide-organosilicate hybrids with improved thermal and optical properties

Abstract: Through hydrolysis and polycondensation of amino-silane with alkyl bridged silane, a new type of polysilsesquioxanes (PSSQ) are obtained. Here we use amine functionalized silane and bis(silyl)ethane to synthesize alkyl chain linked PSSQ. Comparing to conventional polyhedral oligomeric silsesquioxane (POSS), this new silane compound has both enhanced thermal stability and improved compatibility with poly(amic acid). Gelation of this silane compound with poly(amic acid) provides polyimide-organosilicate composite materials. We show that films made from solutions of the composites exhibit higher optical transparency and superior dimensional stability during thermal treatment than films of pure polyimide or of polyimide composites with conventional POSS. Bridging of POSS and chemical bonds between POSS and polyimide chains significantly enhance the physical properties. These results provide useful information to draw molecular architecture for the fabrication of high performance plastic substrates in display devices.