METHOD OF FORMING THIN FILM

摘要

A method of forming a thin film of a vinylidene fluoride homopolymer having an I-form crystal structure, the method being usable for forming the film on various substrates in a relatively easy manner (coating conditions, procedure, etc.); a process for efficiently producing a high-purity vinylidene fluoride homopolymer having an I-form crystal structure; and a novel vinylidene fluoride homopolymer which can give a thin film having excellent ferroelectric characteristics. The method for thin vinylidene fluoride homopolymer film formation comprises (i) a step in which vinylidene fluoride is polymerized by free-radical polymerization in the presence of a C1-20 iodine or bromine compound having at least one moiety represented by -CRf<1>Rf<2>X<1> (wherein X<1> is iodine or bromine; and Rf<1> and Rf<2> are the same or different and each is one selected among fluorine and C1-5 perfluoroalkyls) to produce a raw powder of a vinylidene fluoride homopolymer consisting of the I-form crystal structure alone or comprising the structure as the main component and (ii) a step in which a vinylidene fluoride homopolymer which consists of the I-form crystal structure alone or comprises the structure as the main component and which is obtained from the raw powder of a vinylidene fluoride homopolymer consisting of the I-form crystal structure alone or comprising the structure as the main component is used to form a thin film on a substrate surface.