Simple and rapid micropatterning of conductive carbon composites and its application to elastic strain sensors

The micropatterning of conductive composites is of great importance for the integration of elastic conductors with functional micro-geometries in a stretchable platform. We present a simple and rapid micropatterning method for conductive composites that relies on single-step contact transfer printing (sCTP). A conductive polydimethylsiloxane (PDMS) composite is readily synthesized by dispersing conductive carbon black nanoparticles into a PDMS matrix and is easily patterned on insulative PDMS substrates with negligible dimensional errors by the proposed method. In addition to simplicity and accuracy in fabrication, superior process scalability is revealed through investigation of both multiple-stack and large-area patterning approaches. We also demonstrate an all-elastomeric-platformed piezoresistive strain sensor capable of measuring higher tensile strains compared to conventional metal foil gauges, with highly linear, good cyclic electrical performance, and mechanical robustness. As a potential application, we integrate the strain sensors onto a glove to measure the motions of human fingers in real time. We further demonstrate a rosette-type gauge that can detect both the magnitude and direction of the principal strains with patterning accuracy and uniformity facilitated by the proposed sCTP technique.