Construction of environmentally durable, flame-retardant, and superhydrophobic melamine sponge functionalized with polydopamine and octadecyltrichlorosilane for efficient oil-water separation

Abstract

Special wetting materials have garnered significant interest for oil-water separation applications, owing to the different interfacial behaviors exhibited by oil and water. In this study, superhydrophobic coatings were successfully created on melamine sponge (MS) through the alternating deposition of polydopamine (PDA) and octadecyltrichlorosilane (OTS) layers via dip-coating process. The obtained coating demonstrated a water contact angle (WCA) of 158.9°, whereas the oil contact angle (OCA) was approximately 0°, which was ascribed to the appearance of micro- and nano-scale aggregates firmly attached to the sponge surface. The superhydrophobic/superoleophilic sponge was capable of selectively separating oil from various oil/water mixtures with high efficiency. Meanwhile, selective oil absorption experiments were performed to verify the excellent oil absorption capacity (38.98–130.43 g/g) and efficient oil-water separation performance of the prepared sponge. Furthermore, the superhydrophobic sponge demonstrated exceptional durability under harsh environmental conditions and during extended storage periods. It also displayed outstanding self-cleaning performance, fouling resistance, and flame-retardant properties. Consequently, the superhydrophobic and superoleophilic sponge holds considerable potential for practical applications.