Design and fabrication of polydopamine based superhydrophobic fabrics for efficient oil–water separation

Abstract

In this work, we prepare a PDMS–SiO₂–PDA@fabric with high water contact angle (WCA = 155°). Combining dopamine self-polymerization and a sol–gel method, SiO₂ is in situ grown on a PDA-modified fabric surface to synergistically construct micro–nano rough structures. Finally, a superhydrophobic fabric is successfully obtained after coating the fabric with a layer of PDMS. The prepared fabric can maintain superhydrophobicity after immersion in various solvents (pH = 1, 3, 5, 7, 9, 11, 13, DMF, ethanol, THF, n-hexane) for 24 h and strong ultraviolet irradiation for 60 min. Thanks to the highly reactive PDA clusters, the stronger interfacial bond between the fabric and SiO₂ enables it to withstand 180 min of washing and 159.22 N tensile stress, showing strong adhesion strength. In addition, the modified fabric has excellent self-cleaning properties and is resistant to contamination such as milk, coffee and tea. More importantly, the prepared fabric can selectively repel water and adsorb oil, achieving above 90% oil–water separation efficiency even after 8 cycles.