Novel photothermal response intelligent polyurethane sponge with switching wettability for oil/water separation

Intelligent oil–water separation materials with stimulating response have received extensive attention. In this paper, a novel, cost-effective, and simple approach is developed to produce a photothermal-responsive smart sponge with switchable wettability. The polydopamine (PDA) and photothermal agent copper sulfide (CuS) were grafted PU sponge surface. Thermal-responsive polymers P(VTMS-co-NIPAm) and 1-octadecanethiol (ODT) are then decorated on the PDA/CuS@PU surface through free radical polymerization and Michael addition reaction. The obtained PCPO@PU exhibits rapidly switchable wettability between hydrophobicity and hydrophilicity depending on the temperature response of P(VTMS-co-NIPAm) induced by photothermal effect of CuS. The PCPO@PU showed excellent separation performance with oil absorption ratio 8–33 g·g−1 and average self-desorption efficiency of more than 70%, but also has a remarkable recycling effect. Specifically, the photothermal response of PCPO@PU does not require additional chemical initiation and both address the limitations of materials that respond to specific light species and heat. More importantly, the PCPO@PU is able to realize the fluorescent lamp-peristaltic pump model, which can be a significant step toward its widespread application for oil–water separation in nature marine environment.