One-pot facile fabrication of covalently cross-linked carbon nanotube/PDMS composite foam as a pressure/temperature sensor with high sensitivity and stability

Abstract

Integration of the elasticity of polymers and electrical conductivity of fillers is widely used for the fabrication of composite foams or aerogels as compressible pressure sensors. Due to their poor interface interaction, however, the irreversible change of the spatial position of the conductive fillers in the polymer matrix leads to high noise. Here, we report a flexible and multifunctional temperature/pressure/loading composite foam sensor based on polydopamine functionalized carbon nanotube (PDA-CNT)/polydimethylsiloxane (PDMS). The composite is first obtained through thiol-Michael addition click reaction between poly(3-mercaptopropyl)methylsiloxane (SH-PDMS), vinyl terminated polydimethylsiloxane (vinyl-PDMS) and PDA-CNT, while the composite foam is then afforded by inorganic salt sacrificial template method. When the resulting composite foam sensor is applied to monitor small- and large-scale movements of most parts of the human body, it always generates high stability signals including smooth and stable signal curves due to the strong covalent crosslinking bonds between the matrix and the filler. In addition, the composite sensor also exhibits a multifunctional combining sensing of temperature (25–70 °C), compressive strain (0.1–70%) and loading weight (55–150 g) with high sensitivity, durability and stability, imparting its potential application value in temperature/pressure/loading sensing.