Composite material based on piezoelectric core-shell nanofibers for tactile recognition

In recent years, self-sensing composite materials based on the direct piezoelectric effect have attracted widespread interest as they combine the composite material's mechanical performances with the piezoelectric phase's sensing capability. In this context, piezoelectric nanofibers exhibit minimal impact on the mechanical structure of the composite – differently from bulky films or ceramic disks - and represent a promising strategy for robotic applications or wearable devices. This work aims to develop a self-sensing laminate based on piezoelectric core-shell nanofibers (PEDOT:PSS-based core and P(VDF-TrFE)-based shell). Each layer of the laminate is made of a flexible epoxy material and embeds aligned nanofibers. By orthogonally overlapping two layers, the intersection points of the matrix-like arrangement of the nanofibers generate a network of piezoelectric pixels, which are responsible for sensing. Such a self-sensing composite material exhibited a noticeable capability to recognize the exact position of a mechanical stimulus on its surface.