Patent ID: 8263695

Claim:
An annealed polyvinylidene fluoride (PVDF) composition in the form of a film comprising: a) a polyvinylidene fluoride homopolymer, copolymer or terpolymer, and b) from 0.1 to 20 weight percent of an organically-modified nanoclay based on the weight of the polyvinylidene fluoride polymer and organically-modified nanoclay, wherein said nanoclay platelet surfaces are modified with one or more onium salts, said onium salt having the formula: − X + Y—R 1 R 2 R 3 R 4 wherein X is an anionic center; Y is a cationic center formed from the addition of radicals that create four bonds to that center and may be either a heterocyclic imidazolium + N═R 1 (R 2 R 3 ), a quaternary ammonium, + NR 1 R 2 R 3 R 4 , or a phosphonium + PR 1 R 2 R 3 R 4 ; and R 1 , R 2 , R 3 , and R 4 are each individually H or a C 1-20 group selected from alkyl, aryl, alkylaryl, alkylaryl radicals; wherein said film is piezioelectric, wherein said film is poled and non-stretched, and wherein said composition is annealed at from 130° C. to 180° C. for at least 1 minute after formation of the film.