Multifunctional conductive sponge with excellent superhydrophobicity, piezoresistivity, electro/light to heat conversion, and oil/water separation performance

Flexible porous conductive composites have been widely applied for wearable sensing devices and there is continuous exploration towards multi-functionalization of porous conductive composites. In this work, through sugar template method and following immersion assisted reduction, polydimethylsiloxane (PDMS) sponge embedded with carbonyl iron (CI) was successfully anchored with silver nanoparticles (AgNPs) binded with block copolymer polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS). A superhydrophobic multifunctional sponge type conductive composites (SCC) was prepared (CI-PDMS/AgNPs-SEBS Sponge, abbreviated as CP/AgE Sponge). CP/AgE sponge had excellent superhydrophobic properties (water contact angle≈153°), efficient Joule heating (1.6 V, 101 °C within 180 s) and photothermal conversion capabilities (250 mW/cm2, 102 °C within 40 s). The CP/AgE sponge pressure sensor had excellent piezoresistive properties, including high sensitivity (3.8 kPa−1), wide detection range (160 kPa) and robust stability when subjected to 1000 compression-release cycles, which could be further utilized to accurately and reliably monitor the changing biophysical signals. Besides, CP/AgE sponge had high oil/water separation efficiency as well as magnetically guided waste oil adsorption ability. This work provides a new strategy for preparing a conductive sponge with superhydrophobicity and enriched functionality, which has broad applications in the fields of next generation multifunctional flexible electronics, effective oil/water separation and smart protective skins.