A carbon nanotube-embedded conjugated polymer mesh with controlled oil absorption and surface regeneration via in situ wettability switch.

This paper presents a mesh-type absorbent made of a carbon nanotube (CNT)-embedded polypyrrole dodecylbenzenesulfonate (PPy(DBS)) surface for controlled absorption and release of oils and regeneration of polymer surfaces toward continuous oil/water separation. The mesh absorbs dichloromethane (DCM) under oxidation in aqueous environment and releases them under reduction via in situ switching of underwater wettability. CNTs were grown out of stainless steel surfaces and embedded into the PPy(DBS) film, which enhanced the switchable wettability as well as the surface regeneration. The CNT-embedded morphology improved oil retention by a factor of two in an oxidized state and decreased wettability switch time by 16% in a reduced state over the mesh without CNT embedment during 250 redox cyclic testing. A rolled 2 cm × 3 cm CNT-embedded PPy(DBS) mesh was furthermore used to demonstrate the continuous absorption and release of oils, during which DCM of 16 times of the absorbent weight was collected in 50 redox cycles.