| abstract |
Nanoporous silicone resins and silicone resin films having low dielectric constants and a method for preparing such nanoporous silicone resins. The silicone resin comprises the reaction product of a mixture comprising n (A) 15-70 mol % of a tetraalkoxysilane described by formula n n n Si(OR 1 ) 4 , n n n where each R 1 is an independently selected alkyl group comprising 1 to about 6 carbon atoms, n (B) 12 to 60 mol % of an organosilane described by formula n n n R 4 SiX 3 , n n n where R 4 is selected from the group consisting of alkyl groups comprising 1 to about 6 carbon atoms and phenyl and each X is an independently selected hydrolyzable substituent, n (C) 15 to 70 mol % of an organotrialkoxysilane described by formula n n n R 2 Si(OR 3 ) 3 , n n n where R 2 is a hydrocarbon group comprising about 8 to 24 carbon atoms or a substituted hydrocarbon group comprising a hydrocarbon chain having about 8 to 24 carbon atoms and each R 3 is an independently selected alkyl group comprising 1 to about 6 carbon atoms; in the presence of n (D) water, n (E) hydrolysis catalyst, and n (F) organic solvent for the reaction product. n The silicone resin is cured and heated in preferably an inert atmosphere at a temperature sufficient to effect thermolysis of carbon-carbon bonds of the R 2 groups thereby forming a nanoporous silicone resin. |