Integrated analysis of chain orientation induced anisotropy in nanoimprinted PVDF based copolymers

Poly(vinylidene fluoride) (PVDF) and its copolymers are electrically active materials that have the ability to harvest mechanical energy through mechanical vibrations and structural flexing. Due to the inherent nanoscale dependency of the molecular structure of PVDF copolymer, efficient methods for investigating the effects of chain orientation on its localized nanomechanical properties are very limited. In this manuscript, we use infrared atomic force microscope (IR-AFM), contact-resonance atomic force microscopy (CR-AFM), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (TEM), to reveal the correlations between localized molecular vibration, anisotropy, and the corresponding dynamic nanomechanical properties. IR-AFM is able to probe the chain orientation of the PVDF copolymer and CR-AFM is able to resolve the in-plane anisotropy along the axis of the polymer chain. The combination of these techniques can provide a quick, effective, nondestructive method to reveal the formation mechanisms, which could lead to optimization of the electroactive polymer organization.