Novel reversibly switchable wettability of superhydrophobic–superhydrophilic surfaces induced by charge injection and heating

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.

Preparation of the Temperature-Responsive Superhydrophobic Paper with High Stability

“…Studies have found some common environmentally responsive superhydrophobic surfaces, such as light response, temperature response, pH response, electric field response, ionic liquid response, and magnetic response. − Nowadays, a lot of waste oil and water mixtures are produced in the industrial production process, and superhydrophobic materials can not only separate these mixtures through filtration or single-phase selective absorption, but also realize the free switching of oil–water separation according to production needs in different external environments, which shows their strong industrial application value. Therefore, the preparation of intelligent responsive materials has become an important issue of industrial production. − However, due to the high cost and complex preparation process, their application value in industrial production is limited to a certain extent. , After experimental research and practical verification, it is gradually found that temperature-responsive superhydrophobic surfaces have the advantages of a fast response, low requirement of preparation equipment, and simple preparation process, which make them show a greater production and application value and also set off an upsurge of academic research on temperature-responsive superhydrophobic surfaces. , …”