Ti3C2Tx MXene-Supported Anisotropic Crystallisation of Solvent-Casted p(VDF-TrFE) Films for Improved Elastic Deformation and Piezoelectric Response

Abstract

This study investigates the percolation limit of solvent-casted p(VDF-TrFE) film through its processing (thermal treatment) and the addition of 2D Ti3C2Tx MXene, by evaluating their distribution using SEM-EDX and determining the electroactive crystalline phases using FTIR and XRD spectroscopies, while evaluating the film’s dielectric permittivity and piezoelectric response after a mechanical deformation cycle (elongation). The robust interactions of the -CH2/-CF2 groups of copolymer (55/45 mol%) with the terminal groups (-OH/F) of MXene influence their distributions and alignment along the MXene nanosheets, and, consequently, the higher and anisotropically distributed β-phase crystallinity near its percolation limit (0.0015 w/w% of loading). This exhibited a piezoelectric behaviour of d33 ~19 pC/N after e-polishing and ~24 pC/N after 50% of elongation performed at an ambient temperature. Such an interconnected and uniform film achieves a dielectric permittivity of ~22, exhibits intrinsic flexibility (fracture resistance), and facilitates effective load transfer during elastic deformation while maintaining the piezoelectric response, which could not be achieved for a pure p(VDF-TrFE) film.