Pressure-sensitive carbon black/graphene nanoplatelets-silicone rubber hybrid conductive composites based on a three-dimensional polydopamine-modified polyurethane sponge

Development of pressure sensors which display high sensitivity, and are flexible, inexpensive, and easy to manufacture has drawn significant interest due to their diverse applications such as tactile skin sensors (e.g. electronic skin), pulse detectors, speech recognition elements, and others. A novel flexible piezoresistive sensor comprising a conductive carbon black/graphene nanoplatelets coated elastomeric polymer sponge is presented. The piezoresistive sponge is prepared through a simple layer-by-layer (LbL) assembly method in which carbon black/graphene nanoplatelets (CB/GNPs) particles and silicone rubber (SR) are alternantly coated upon an polydopamine-modified polyurethane sponge(PU sponge) framework. The hybrid sponge piezoresistive sensor exhibits excellent functionalities, including enhanced sensitivity(0.38 kPa⁻¹), excellent stability (>10 loading/unloading cycles), high specific strength, good elasticity, and high compressibility. In addition, the LbL assembly technology of preparing CB/GNPs-SR hybrid sponge shows large superiority in programmable fabrication way. Application of the sensor is demonstrated for the detection of various external stimuli such as sound-driven vibrations, muscle motions.