Preparation of a novel Janus-cotton via the in-situ dual-phase formation and volatilization-induced fabrication method for oil/water separation with single and double layers

The asymmetric wettability of Janus membranes has continuously drawn attention in various fields. In this paper, a Janus-cotton was prepared via a novel method using in-situ dual-phase formation and volatilization-induced fabrication. The n-hexane suspension of PDMS and SiO2 was used to coat one surface of the water-wetted cotton fabric to form an in-situ dual-phase (n-hexane/water), where Janus-cotton was then prepared by volatilization and heating. One side of the prepared Janus-cotton was superhydrophobic, with a water contact angle of 151.1 ± 1.8°, while the other side was superhydrophilic with a water contact angle of 0°. This Janus-cotton can realize directional transport of water. Single layer Janus-cotton successfully separates lighter oil-water mixtures with the separation efficiency of 98%, while double layers can separate heavier oil-water mixture with the separation efficiency of 95%. Moreover, it has excellent water collection ability in oil. [Display omitted] •Janus-cotton prepared via a novel method using in-situ dual-phase formation and volatilization-induced fabrication.•Separation of both light and heavy oils from water.•Directional transport of water and excellent water collection ability in oil.•First application of double-layer Janus-cotton for heavy oil separation from water.