Formulating Multiphase Medium Anti-wetting States in an Air-Water-Oil System: Engineering Defects for Interface Chemical Evolutions

Zhongxin Ping; Qingyun Sun; Jiuqi Yi; Qianqian Li; Lukang Zhao; Hui Zhang; Fangzhi Huang; Shikuo Li; Longjiu Cheng

doi:10.1021/acsami.1c15823

Formulating Multiphase Medium Anti-wetting States in an Air-Water-Oil System: Engineering Defects for Interface Chemical Evolutions

ACS Appl Mater Interfaces. 2021 Oct 20;13(41):49556-49566. doi: 10.1021/acsami.1c15823. Epub 2021 Oct 12.

Authors

Zhongxin Ping¹, Qingyun Sun¹, Jiuqi Yi¹, Qianqian Li¹, Lukang Zhao¹, Hui Zhang¹, Fangzhi Huang¹, Shikuo Li¹, Longjiu Cheng¹

Affiliation

¹ Laboratory of Clean Energy & Environmental Catalysis, AnHui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601, P. R. China.

PMID: 34636235
DOI: 10.1021/acsami.1c15823

Abstract

Studies which regulate macroscopic wetting states on determined surfaces in multiphase media are of far-reaching significance but are still in the preliminary stage. Herein, inspired by the wettability subassembly of fish scales, Namib desert beetle shell, and lotus leaf upper side, interfaces in the air-water-oil system are programmed by defect engineering to tailor the anti-wetting evolution from double to triple liquid repellency states. By controlling the visible light irradiation and plasma treatment, surface oxygen vacancies on Cu_xO@TiO₂ nanowires (NWs) can be healed or reconstructed. The original membrane or the membrane after plasma treatment possesses abundant surface oxygen vacancies, and the homogeneous hydrophilic membrane shows only double anti-wetting states in the water-oil system. By the unsaturated visible light irradiation time, the surface oxygen vacancy partially healed, the heterogeneous hydrophilic-hydrophobic components occupied the membrane surface, and the anti-wetting state finally changed from double to triple in the air-water-oil system. After the illumination time reaches saturation, it promotes the healing of all surface oxygen vacancies, and the membrane surface only contains uniform hydrophobic components and only maintains double anti-wetting state in the air-oil system. The mechanism of the triple anti-wetting state on a heterogeneous surface is expounded by establishing a wetting model. The wetting state and the adhesion state of the Cu_xO@TiO₂ NW membrane show regional specificity by controlling the illumination time and region. The underwater oil droplets exhibit the "non-adhesive" and "adhesive" state in a region with unsaturated irradiation time or in an unirradiated region, respectively. Underwater oil droplet manipulation can be accomplished easily based on switchable wettability and adhesion. Current studies reveal that defect engineering can be extended to anti-wetting evolution in the air-water-oil system. Constructing an anti-wetting interface by heterogeneous components provides reference for designing the novel anti-wetting interface.

Keywords: CuxO@TiO2 NWs; defect engineering; droplet manipulation; homogeneous−heterogeneous interface chemistry; switchable wettability; triple anti-wetting evolution.