Self-assembled PPy@COF micro/nanostructure on flexible cotton fabric enables all-weather cleanup of high-viscosity crude oil via synergistic photothermal, electrothermal, and superhydrophobic effects

Frequent oil spills pose severe environmental and ecological threats, necessitating the development of materials capable of effective all-weather remediation of high-viscosity crude oil. In this study, a self-assembly strategy was employed to integrate covalent organic framework (COF) and polypyrrole (PPy) on a flexible cotton fabric (CF). Subsequent hydrophobic modification with polydimethylsiloxane (PDMS) produced a multifunctional composite membrane (PDMS@PPy@COF@CF) that integrated photothermal conversion, electrothermal response, and superhydrophobicity. The membrane exhibited excellent superhydrophobicity (WCA = 153.5°), superior oil-water separation efficiency (≥98.5%), and a high separation flux (≥24 010.4 L m – 2 h –1 ). Notably, the construction of micro/nanostructures via π-π stacking and hydrogen bonding between PPy and COF layers endowed the material with outstanding photothermal and electrothermal conversion performances. Specifically, the surface temperature rapidly increased to 73.8 °C within 180 s under 1.0 kW m – 2 irradiation and attained 145.9 °C at 10 V. Synergistic utilization of photothermal (0.5 kW m – 2 ) and electrothermal (4 V) effects enabled rapid crude oil adsorption within merely 45 s. Furthermore, the composite membrane maintained stable conductivity and superhydrophobicity under mechanical strain, ensuring its reliability and durability for practical applications. In summary, the multifunctional PDMS@PPy@COF@CF membrane enables energy-efficient all-weather cleanup of high-viscosity crude oil spills with practical oil recovery potential.