A multifunctional bioinspired superhydrophobic sponge with photothermal conversion and flame retardancy for integrated oil-water separation and viscous oil remediation.

The frequent occurrence of crude oil spills and industrial organic emissions has posed a serious threat to the ecological environment and public health. Inspired by the spindle-knot structure of spider silk, a biomimetic multifunctional sponge (PDMS@CMS) with excellent photothermal conversion and flame retardancy properties was successfully fabricated through low-temperature carbonization and polydimethylsiloxane (PDMS) hydrophobic modification. The PDMS@CMS can efficiently capture oil drops from the air because of the unique periodic spindle-knot structure, which significantly reduces fire hazards. Under light irradiation, the sponge surface undergoes rapid heating to over 140 ℃ within 300 s, enabling efficient adsorption and removal of high‑viscosity crude oil. The PDMS@CMS exhibited superior thermal stability and flame‑retardant properties. The experimental results demonstrate that the PDMS@CMS exhibits a water contact angle of 155.2° and outstanding adsorption capacities for various oils and organic solvents (61.86-168.04 g·g-1). Meanwhile, a high separation efficiency of 97.9% is maintained after 10 consecutive oil-water separation cycles. Furthermore, the material demonstrates excellent mechanical and chemical durability, as well as remarkable reusability. Moreover, the PDMS@CMS sponge can effectively separate surfactant-stabilized oil-in-water emulsions. The present work provides a promising and adaptable strategy for efficient oil spill remediation and environmental cleanup.