Rapid response of polyvinylidene fluoride films to vapor stimuli: Role of polymorphic phase fractions

Bioinspired three-dimensional shape deformations of smart polymers in response to stimuli such as light, vapor, and external fields have garnered significant attention in the field of soft robotics. Among these stimuli, vapor-induced shape deformation is particularly promising due to its ability to generate substantial deformation in response to minimal vapor input. In this study, we investigated the influence of polymorphic phase fractions of polyvinylidene fluoride (PVDF) films on the actuation behavior upon exposure to acetone vapor. Our findings reveal that the actuation characteristics of PVDF films strongly vary with the polymorphic phase fraction. Notably, maximum actuation is observed at a specific phase ratio of β to α (52:48) in the PVDF film. Finite element analysis was conducted to provide deeper insights into the impact of varying polymorphic phase fractions on the actuation performance of PVDF films, supporting and corroborating the experimental observations.