Interfacial swelling engineered superhydrophobic and electrically conductive coatings for multifunctional piezoresistive sensors

Conductive foam composites (CFCs) based pressure sensors show promising applications in flexible electronics, but it is still difficult to develop cost-effective methods for preparation of multifunctional CFC pressure sensors with a large working strain and environment tolerance. Herein, a facile "carbon nanotubes (CNTs) decoration and simultaneous hydrophobization" method is proposed to fabricate electrically conductive and superhydrophobic foam composites. CNTs/stearic acid (SA) are anchored onto the skeleton of the partially swelled styrene-butadiene rubber (SBR) foam via one step ultrasound-assisted interface sintering. The obtained superhydrophobic SA/CNTs decorated foam composites (SCFCs) with strong interfacial adhesion exhibit outstanding corrosion resistance and durability. SCSF piezoresistive sensors show a wide compressive strain sensing range (10–95 %) and a great durability over 11,000 cycles and can work normally in underwater or even corrosive conditions. In addition, SCFCs possess excellent photothermal conversion performance and their resistance exhibits negative temperature coefficiency, making them promising as temperature sensors.