Fabrication and Properties of Thermochromic Superhydrophobic Coatings

Herein, thermochromic superhydrophobic coatings (TSCs) with different colors are prepared, and their surface wettabilities and optical properties are studied. The TSC coating maintains its surface superhydrophobicity even after a series of mechanical damage (sandpaper abrasion, gravel impact, and knife scratching), chemical corrosion, ultraviolet aging, and environmental temperature changes. Contaminants on the surface of the coating sre easily washed by water droplets. The TSC has a reversible color function with a critical discoloration temperature (T-c) approximately in the range 28-31 degrees C. In winter, the ambient temperature (T-a) is lower than T-c, and the TSC is dark and absorbs more solar energy. Although in summer, T-a > T-a, the TSC is light and reflects more solar energy. The sunlight exposure test shows that the surface temperature of the thermochromic pigment/polydimethylsiloxane (TP/PDMS) coating in winter is only 0.9 degrees C lower than that of the carbon black/PDMS (CB/PDMS) coating, whereas in summer, the surface temperature of the TP/PDMS coating is only 6.2 degrees C higher than that of TiO2/PDMS coating. Energy consumption simulation results show that the TP/PDMS coating decreases the total annual energy consumption in North China by 13.74% compared with the traditional white cooling coating.

Automated summary

Thermochromic superhydrophobic coatings with reversible color function were prepared and studied in this work, showing excellent superhydrophobicity and color-changing properties in response to different environmental temperatures. The coatings demonstrated potential for energy saving by reflecting or absorbing solar energy based on the environmental temperature.