Superwettability‐based separation: From oil/water separation to polymer/water separation and bubble/water separation

Abstract

The separation of oil/water mixtures, polymer/water mixtures, or bubble/water mixtures has broad applications. In this paper, we aim at extending the well‐developed wettability‐based oil/water separation strategy to separate the mixtures of liquid polymers and water and separate bubbles from water. The micro/nanostructures are simply produced on a stainless steel mesh by femtosecond laser treatment to endow the mesh with superhydrophilicity in the air and superoleophobicity, superpolymphobicity, and superaerophobicity in water. The underwater superoleophobicity, superpolymphobicity, and superaerophobicity enable the structured mesh to have the ability of oil/water separation, polymer/water separation, and bubble/water separation. Water can pass through the mesh due to the superhydrophilicity of the laser‐structured mesh. Whereas, the oils, the liquid polymers, and the bubbles in water are intercepted by the structured mesh because such a water‐wetted mesh has strong repellence to oils (underwater superoleophobicity), liquid polymers (underwater superpolymphobicity), and bubbles (underwater superaerophobicity). As a result, the oil, the liquid polymer, and the bubble are successfully separated from water by using the as‐prepared superwetting mesh. We believe that the diversified wettability‐based separation processes will have wide potential applications in environmental protection, energy utilization, industrial manufacture, agricultural production, and so on.

Structured Copper Mesh for Efficient Oil-Water Separation Processed by Picosecond Laser Combined With Chemical Treatment or Thermal Oxidation

“…For the pristine copper mesh, the CA is 127 °± 2.3 °. By using this processing system, a 1.5 × 1.5 cm 2 region is processed in less than 1 min (the scanning speed and scanning period is 1,000 mm/s and 10 μm, respectively), which is quicker than previous studies (Duan et al, 2018;Kai et al, 2018;Yong et al, 2018;Yong et al, 2021).…”

Nature-Inspired Superwettability Achieved by Femtosecond Lasers

“…The trapped water supports a Cassie contact state between underwater liquid polymer and the structured surface, thus allowing the material to repel liquid polymers [90]. The properties of polymer repellence can be used to reduce the adhesion of polymers to material surfaces, design polymer shapes, and separate polymers from water [90,[204][205][206][207][208]. Underwater superpolymphobicity will have significant potential applications in polymer production, packaging, casting industry, polymer molding, 3D printing, and other fields related to polymers.…”

Emerging Separation Applications of Surface Superwettability

“…The significant polymer repellence allows the underwater superpolymphobic materials to potentially be used to separate the mixtures of water and liquid polymers [15,298,302]. Yong et al obtained underwater superpolymphobicity on a stainless-steel mesh via femtosecond laser treatment [302].…”

“…They are usually interwoven with each other to form different kinds of mixtures. The separations of gas, liquid, and solid multiphase mixtures are of great significance [11][12][13][14][15]. Various separation materials and methods have been developed to separate the multiphase mixtures [16][17][18][19][20][21][22][23][24][25].…”