Ultrasmall barium titanate nanoparticles modulated stretchable dielectric elastomer sensors with large deformability and high sensitivity

Large deformability and high sensitivity is difficult to be realized simultaneously in flexible sensors. Herein, taking advantage of the high permittivity and highly active surfaces of the ultrasmall barium titanate nanoparticles (BT NPs) and the high stretchability of the p(BA-GMA) elastomer matrix, we propose a high-performance soft stretchable sensor. The addition of the ultrasmall BT NPs can not only increase the permittivity and capacitance of polyacrylate-matrix composite dielectric material to obtain a high sensitivity, but also basically maintains the excellent mechanical properties of the polymer matrix. The dielectric constants of the composite films increase from 5.68 to 13.13 at 10 kHz with the increase of BT NPs content from 0 to 15 vol.%, which results in a high capacitance of 236.16 pF for 15 vol.% BT/p(BA-GMA) sensor. Combining the high permittivity and the large deformability (a maximal deformation of 87.2%), the 15 vol.% BT/p(BA-GMA) sensor has high sensitivity and shows high linearity and stable output even if under dynamic measurement. The dual-mode sensor that utilizes the orthogonality of capacitance-resistance is designed, which shows excellent performance in monitoring human body movements and noncontact measurement. The results present that the BT/p(BA-GMA)-based sensor has high stability and reliability not exceed 65?, which can meet the application requirements in dynamic monitoring.