Abstract
Reversibly switching wettability between superhydrophobicity and superhydrophilicity has attracted widespread interest because of its important applications. In this work, we propose a reversible superhydrophobic–superhydrophilic conversion induced by charge injection and heating. Different from the conventional electrowetting phenomenon caused by the accumulation of solid–liquid interfacial charges, we discovered a phenomenon where charge injection and accumulation at the solid surface results in a sharp increase in wettability. The wettability of a sprayed SiO2 nanoparticle coating on a glass slide was shown to change from superhydrophobic to superhydrophilic by charge injection and heating, and the superhydrophobicity was restored by heating, verifying a reversible superhydrophobic–superhydrophilic conversion. The influence of voltage, temperature, and time on the coating wettability and its durability under reversible conversion have been studied.
Highlights
Surfaces that are capable of reversibly switchable wettability have attracted increasing interest, especially those able to switch between superhydrophobicity and superhydrophilicity, and the effects of external stimuli on surface wettability have been explored extensively
It is obvious that after spraying, the glass-slide surface became rough with a large number of particles that formed irregular micro- and nanoscale composite structures, which increased the roughness of the coating surface and changed the wettability of the coating into superhydrophobic
After 2 days and 10 days at room temperaspeculated that the reason for the enhanced wettability transition from superhydrophobic to superhydrophilic with increasing temperature may be the following: the increase of temperature will promote the thermal motion of the molecules in the solid, which in turn will help the charges inject into the solid surface during the process of electric field application
Summary
Surfaces that are capable of reversibly switchable wettability have attracted increasing interest, especially those able to switch between superhydrophobicity and superhydrophilicity, and the effects of external stimuli on surface wettability have been explored extensively. The surface wettability of the coating changed from superhydrophobic to superhydrophilic and was restored by heating.
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