Liu W, Xiang S, Liu X, Yang B. Underwater Superoleophobic Surface Based on Silica Hierarchical Cylinder Arrays with a Low Aspect Ratio.
ACS NANO 2020;
14:9166-9175. [PMID:
32644775 PMCID:
PMC7460563 DOI:
10.1021/acsnano.0c04670]
[Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
A superantiwetting surface based on low-aspect-ratio hierarchical cylinder arrays (HCAs) was successfully obtained on a silica substrate by colloidal lithography with photolithography. Colloidal lithography is a technique involving transfer of a pattern to a substrate by etching or exposure to a radiation source through a mask composed of a packed colloidal crystal, while photolithography is utilized by which a pattern is transferred photographically to a photoresist-coated substrate, and the substrate is subsequently etched. The surface provides an alternative approach to apply aligned micro-nano integrated structures with a relatively low aspect ratio in superantiwetting. The obtained HCAs successfully integrated micro- and nanoscale structures into one system, and the physical structure of the HCAs can be tuned by modulating the fabrication approach. Using a postmodification process, the underwater-oil wetting behavior of cylinder-array based surfaces can be easily modulated from the superoleophobic state (an oil contact angle (OCA) of 161°) to oleophilic state (an OCA of 19°). Moreover, the underwater-oil wettability can be reversibly transformed from the superoleophobic state (an OCA of approximately 153°) into the oleophilic state (an OCA of approximately 31°) by grafting stimuli-responsive polymer (PNIPAAm) brushes onto this specific hierarchical structure. Due to the temperature-responsive property, modifying the surface with PNIPAAm provides a possibility to control the oil wettability (repellent or sticky) by temperature, which will benefit the use of HCAs in oil-water separation and other application fields.
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