In situ nanoscale insights into the piezoresponse in ferroelectric composite fiber

Abstract

PVDF-based nanocomposites with robust piezoelectric response have attracted significant attention, yet a full understanding of the molecular-level interactions between PVDF and nanofillers remains challenging. In this work, using carbon nanotube (CNT)-doped PVDF fibers as a representative composite system, we investigated the in situ nanoscale piezoresponse and the interface behavior between the PVDF matrix and CNT nanofillers through a combination of piezoresponse force microscopy and atomic force microscopy-infrared spectroscopy (AFM-IR). Taking advantage of the nanoscale resolution of AFM-IR, a characteristic peak shift, providing direct evidence of the CH–π interaction between CNTs and PVDF, was revealed. Moreover, the distribution of the β-phase content in a single fiber was obtained through AFM-IR chemical mapping. A concentration-dependent polarization of PVDF by CNTs was clearly observed, which provided insight into the nanoscale dipole alignment and phase construction in PVDF-based nanocomposites. In this work, a direct in situ nanoscale analysis of the interfaces in PVDF-based nanocomposites was conducted, opening avenues for designing nanocomposites with improved performance.