A mechanically and piezoelectrically anisotropic polymer thin film is formed from a crystallizable polymer and an additive configured to interact with the polymer to facilitate chain alignment and, in some examples, create a higher crystalline content within the polymer thin film. The polymer thin film and its method of manufacture may be characterized by a bimodal molecular weight distribution where the molecular weight of the additive may be less than approximately 5% of the molecular weight of the crystallizable polymer. Example polymers may include vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, and vinyl fluoride. Example additives may occupy up to approximately 60 wt. % of the polymer thin film. The polymer thin film may be characterized by a piezoelectric coefficient (d31) of at least approximately 5 pC/N or an electromechanical coupling factor (k31) of at least approximately 0.1.