Fluorine-free preparation of superhydrophobic polyester fabric with directional moisture transport for efficient oil-water separation

Since the negative impact of fluorinated substances on human health and the environment, fluorine-free superhydrophobic surfaces are the alternative approach that has received growing attention and progress. Herein, a fluorine-free superhydrophobic polyester fabric (D4H-PF) with directional moisture transport was facilely fabricated through plasma-induced polymerization of octamethylcyclotetrasiloxane (D4) for efficient oil-water separation. To obtain asymmetric wettability, a hydrophilic finishing agent (HFA) was sprayed on the other side of the polyester fabric. After plasma treatment, the water contact angle (WCA) of the polyester fabric has been significantly enhanced from 79° to 153.31°, thereby achieving superhydrophobicity. The directional moisture transport endowed D4H-PF with an efficient oil-water separation efficiency for both light oil/water mixture (98.88%) and heavy oil/water mixture (92.24%). Meanwhile, the D4H-PF has high permeation fluxes of 4968.15 L/(m2·h) and 4872.61 L/(m2·h), respectively. Meanwhile, D4H-PF showed suitable mechanical stability, acid-base tolerance, and washability for practical application. Therefore, D4H-PF with directional moisture transport service is a promising potential candidate for sustainable and effective oil-water separation. This study not only extends the application scope of plasma but also offers useful insights into the designing of eco-friendly superhydrophobic surfaces.