BaTiO3/MXene/PVDF-TrFE composite films via an electrospinning method for flexible piezoelectric pressure sensors

Abstract

Flexible piezoelectric pressure sensors have a great application prospect in wearable electronic products due to the advantages of low cost, fast response speed and a self-powered system. However, traditional films based on piezoelectric ceramic/polymer materials face problems such as poor dispersion and insufficient polarization, which hinder the piezoelectric performance of pressure sensors. In this work, MXene was introduced to modify the surface of barium titanate (BaTiO₃), which was blended with poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) matrix. An electrospinning method was adapted to fabricate BaTiO₃/MXene/PVDF-TrFE composite films. This work proposed a new microscopic sensing mechanism. In addition, this MXene-modification strategy could improve the dispersion of BaTiO₃ into the PVDF-TrFE matrix, increase the polarization efficiency and enhance the piezoelectric performance of the sensors. The results showed that the composite film with 0.15 wt% MXene could achieve a remarkable output voltage of 7.6 V. In addition, the tensile strength of the composite film with 0.15 wt% MXene (20.8 MPa) was 77.8% higher than that without MXene (11.7 MPa). Meanwhile, the β phase content of the composite film could reach 81.04%, and the crystallinity increased from 39.49% to 50.31%. The fabricated piezoelectric pressure sensor had a wide detection range (0.2–400 kPa) and a short response time (56 ms). Besides, even after undergoing over 5000 compression cycles, it maintained a stable piezoelectric response. This pressure sensor could quickly respond to joint movements and strenuous exercises in humans. Therefore, this pressure sensor showed great advantages and potential in the application of human motion monitoring.