Fabrication of solar-reflective, hydrophobic polymer materials with excellent cooling and anti-icing properties through selective etching

Polymeric cool roofing materials have been concerned all along for their promising applications in energy-saving fields. Simultaneously, anti-icing property is another significant consideration for roofing materials. Herein, porous surfaces were constructed through immersing poly(methyl methacrylate) (PMMA)/chlorinated polyethylene (CPE) blending sheets in cyclohexane/methylbenzene/acetone (90/10/10) mixed solvent to selectively etch some components, and their cooling and anti-icing properties were investigated. Both solar reflectance (R_{so l}) and thermal emissivity (ε_T) at atmospheric window (8–13 µm) of porous sample with 30 wt% CPE (R_{so l} = 93.7%, ε_T = 87.1%) were higher than those of pure PMMA (R_{so l} = 13.0%, ε_T = 86.4%). The porous sample with 30% CPE as a simulated roof possessed the best cooling performance from cooling test: its final temperature was only 25.3 °C after 1 h solar radiation, 27.1 °C lower than that of pure PMMA. Moreover, the porous sample with 30 wt% CPE exhibited very hydrophobic and good anti-icing properties. The freezing point and the freezing time of water on the hydrophobic surface were −24.4 °C and 568 s, 7.2 °C lower and 452 s longer than those of water on the surface of pure PMMA, respectively. We believe that this solar-reflective and anti-icing porous material has potential application for the next-generation roofing material.