PVDF thin films having high electromechanical efficiency and a gel casting method for forming same

Abstract

A mechanically and piezoelectrically anisotropic polymer thin film may be formed by gel casting a solution that includes a crystallizable polymer and a liquid solvent. The solvent may be configured to interact with the polymer to facilitate chain alignment and, in some examples, create a higher crystalline content within the cast thin film. The thin film may also include up to approximately 90 wt. % of an additive and may be characterized by a bimodal molecular weight distribution of a crystallizable polymer where the molecular weight of the additive may be less than the molecular weight of the crystallizable polymer. In some examples, the polymer(s) and the additive(s) may be independently selected from vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinyl fluoride, etc. The anisotropic polymer thin film may be characterized by an electromechanical coupling factor (k31) of at least 0.1.

Dependencies are inferred from the claim text.