Fabrication of a Bio‐Based Superhydrophobic and Flame‐Retardant Cotton Fabric for Oil–Water Separation

Abstract It is an urgent task to develop environmentally friendly and flame retardant durable oil–water separation materials. A green TA/B@PDA coating derived from bio‐based materials such as tannic acid (TA), borax (B), and polydopamine (PDA) is deposited on cotton fabric through facile dip‐coating method and step‐by‐step assembly method. A series of methods are used to characterize the as‐prepared cotton fabric. PDA provides a reactive interface, while n‐dodecyl mercaptan enhances the hydrophobicity of the surface with a water contact angle (WCA) and shedding angle (SA) of 153.3° ± 1.2° and 9° ± 0.8°, respectively. The as‐prepared fabric exhibits outstanding oil/water separation efficiency (>98.5%) for various types of oil, and wear resistivity, washability, and reusability. Meanwhile, combustion test and limit oxygen index (LOI) test show that the modified fabric has excellent flame retardant performance. The cone calorimeter test (CCT) indicates that compared with the pristine cotton fabric, the peak heat release rate (PHRR) and total heat release (THR) of the TA/B@PDA cotton is decreased by 50% and 32%, respectively. Through the analysis of char residues, the flame retardant mechanism is studied. This method provides a general green way for the construction of superhydrophobic surfaces, and can be further applied to the broad fields of durable oil–water separation.