Self-polarized poly(vinylidene fluoride) (PVDF) films were prepared via solution crystallization technique wherein the polymorphism of the films was controlled from alpha phase (>85%) to gamma phase (>90%) by varying the time of ultrasonication. On increasing ultrasonication time up to 60 min, gamma phase crystallites were found to be self-aligned in the matrix while an equal proportion of alpha and gamma phases coexist in the PVDF films ultrasonicated for 120 min. The phase conversion as well as inversion was evident from Fourier transform infrared, X-ray diffraction, and differential scanning calorimetry analyses. Microscopic images of films ultrasonicated for 60 min showed a scrolled lamellar morphology while those sonicated for 120 min showed mixture of scrolled lamellar and spherulitic morphology. With the help of computational studies, it is explained that a large amount of energy is required for transforming trans-gauche-trans-gauche into trans-trans-trans-gauche conformation which is provided by ultrasonication. The mechanism of gamma phase formation is proposed based on the experimental and theoretical approaches. Our studies show that just by tuning the time of ultrasonication, PVDF films with various morphologies can be processed; either one with predominantly electroactive gamma phase with superior electrical properties or one with equal proportion of alpha and gamma phases with superior mechanical properties. (c) 2018 Wiley Periodicals, Inc.