Preparation of Fluorine-Free Superhydrophobic Paper with Dual-Response of Temperature and pH

Abstract

Although various superhydrophobic materials have been manufactured and effectively used for oil–water separation, it is still highly desirable to explore materials which are eco-friendly, low-cost, and multifunctional. In this paper, a stable copolymer solution was prepared from the fluorine-free superhydrophobic copolymer with dual-responsiveness of temperature and pH. The functional superhydrophobic paper was prepared by immersing paper in copolymer solution by the dip-coating method. The surface element and structure analysis of the prepared superhydrophobic paper shows that the dual-responsive copolymer adheres successfully to the surface of the paper without destroying the fiber structure of the paper. At pH ≥ 7 and T > 25 °C, the paper has a good superhydrophobic performance, while under the conditions of pH < 7 and T < 25 °C, the paper comes into a hydrophilic state. Therefore, the dual-responsive superhydrophobic paper is more likely to adapt to the complicated oil-water separation environment than the single-response.

Preparation of the Temperature-Responsive Superhydrophobic Paper with High Stability

“…It can be seen from Figure that there is little influence on the critical temperature change before and after polymerization, and the temperature response block is the PNIPAAm block in the polymer, which indicates that the phase transition temperature of the polymer is about 32 °C. Theoretically, when the temperature is above the LCST, the temperature-responsive polymer exhibits superhydrophobicity, and when the temperature is below the LCST, the temperature-responsive polymer exhibits hydrophilicity. , …”

“…Theoretically, when the temperature is above the LCST, the temperature-responsive polymer exhibits superhydrophobicity, and when the temperature is below the LCST, the temperature-responsive polymer exhibits hydrophilicity. 38,39 In the experiment, we also determined the critical response temperature of the modified paper by gradually narrowing the temperature range. In the specific operation, we have prepared several oil−water mixtures at different temperatures, and observed the separation state of these oil−water mixtures by the paper.…”

A Review of Recent Advances in the Development of Superhydrophobicity over Various Substrate Surfaces Using Polymers

“…As a result, the paper shows superhydrophobicity. Thus, the developed paper can be extensively used in moisture‐proof packing and other fields [63] …”

Magnetically Responsive Superhydrophobic Surfaces with Droplet Manipulation Capability

“…This excellent wetting control ability can be applied to various scientific and industrial fields such as chip manufacturing, [1] biomedicine, [2] wind power generation, [3] aerospace, [4] sensing response, [5] surface self-cleaning, [6,7] nondestructive droplet transportation, [8] etc. At present, most of the methods used to control surface wettability are stimulation control, and these stimuli include light, [9,10] electric field, [11] high temperature, [12,13] pH value, [14,15] physical strain, [16,17] magnetic field, [18,19] etc. Among them, the magnetic response has attracted extensive attention because of its remote control, fast response speed, and no influence on other physical and chemical properties of the material surface.…”