Ti3C2Tx MXene-Ag/silicone rubber composites with enhanced dielectric properties and improved mechanical properties

Abstract

Conductive filler/polymer composites were widely used in dielectric devices, but high dielectric constant was accompanied by high loss tangent. Incorporating highly conductive fillers into silicone rubber (SR) matrix may be a feasible way, since the loss tangent of SR is extremely low. In this paper, to improve the dielectric properties of polymer composites, SR composites were fabricated with Ag decorated Ti3C2Tx MXene (Ti3C2Tx MXene-Ag) as the fillers. The thermal stabilities, dielectric and mechanical behaviors of the Ti3C2Tx MXene-Ag/SR composites were investigated. Compared with Ti3C2Tx MXene/SR composites, Ti3C2Tx MXene-Ag/SR composites exhibit higher dielectric constants, due to the deposition of Ag particles on the surfaces of Ti3C2Tx MXene nanosheets. The dielectric constant of Ti3C2Tx MXene-3.2Ag/SR composites is 7.29 (17.8% higher than MXene/SR composite and 162% higher than SR), and the loss tangent is as low as 0.00114 at 1 kHz. The enhanced interfacial polarization and micro-capacitor model can be used to explain the improved dielectric properties of the composites. Furthermore, the prepared SR composites have excellent mechanical properties, with a tensile stress of 554 kPa and an elongation at break of 257%. This work illustrates a method to obtain polymer-based composites with high dielectric and mechanical performances, which can be used as dielectric elastomers in actuators, sensors, biomedicine, energy collector and so on.