Eco-friendly superwettable functionalized-fabric with pH-bidirectional responsiveness for controllable oil-water and multi-organic components separation

Abstract

Smart materials with controllable wettability have become one of the current research hotspots. Among them, the pH-responsive superwetting material is considered an ideal material because of its rapid response process and simple response mechanism. However, the pH-responsive materials reported previously could only perform wettability conversion in a single direction. In order to meet the demands of practical applications, it is indispensable to prepare the pH-bidirectional responsive superwetting material which can flexibly transform wettability in both directions. Based on this, a fluorine free and eco-friendly superwetting fabric with pH-bidirectional responsiveness was prepared by free radical polymerization and the combination of micro-nano hierarchical structure. A series of test results verified that the prepared fabric possessed excellent mechanical durability and chemical stability, satisfactory flux and separation efficiency. In addition, this work also successfully employed the prepared pH-bidirectional responsive superwetting fabric to realize the separation of three-phase oil-water-oil mixture. Surprisingly, the prepared fabric was also proved to be effective for the separation of multiple organic components, which was rarely reported in previous researches. Therefore, such pH-bidirectional responsive superwetting fabric will have broad application prospects in the field of oil-water separation and multi-organic components separation under the actual complex environment. In this paper, a functionalized-fabric with pH-bidirectional responsiveness was obtained by a low-cost, environmentally friendly and simple preparation process. The micro-nano hierarchical rough structure and the sensitive groups of acid and alkaline were integrated on a piece of fabric. The surface of this smart fabric exhibited superhydrophobicity-superoleophilicity in a neutral environment, and would transform into superhydrophilicity-underwater superoleophobicity under external stimulations of acid and alkaline, showing a flexible bidirectional wettability transformation. It was worth noting that the obtained fabric could separate various oil-water mixtures and successfully achieve the separation of three-phase oil-water-oil mixtures. Surprisingly, the resulted smart fabric could efficiently separate two noxious components (phenol and aniline) from the mixed organic phase. Therefore, this functionalized fabric will provide new insights for the application of oil-water separation and organic component separation materials, and can be expanded to the fields of pharmaceutical production, dye industry and chemical processes. • Bidirectional wettability conversion in the entire pH-range. • The fabrics can realize high-flux and high-efficient oil-water separation. • In-situ and continuous three-phase oil/water/oil mixtures separation. • The fabrics can separate multiple organic components (phenol, aniline, anisole). • The fabrics exhibit excellent durability and reusability.