A super-hydrophobic composite coating with near-infrared low reflection and low emissivity of 8-14 μm

In this paper, a PDMS modified PU/Al-Sm2O3 composite coating with super-hydrophobic properties, near-infrared low reflectivity, and low emissivity of 8-14 mu m was successfully prepared by a simple glass rod coating method. The effects of the mass ratio between the PU and PDMS, the curing temperature, the total addition amount of the functional fillers of Al and Sm2O3, and the mass ratio of composite fillers and nano-SiO2 on the overall performance of the coating were systematically discussed. The results show that a higher amount of functional composite fillers and curing temperature are beneficial to achieve a lower emissivity of the coating, but the effect on the near-infrared reflectivity of the coating is not obvious. In the optimal coating formulation system, modifying the coating with an appropriate amount of nano-SiO2 can form a clear papillary micro-nano rough structure on the surface of the coating, thereby making the coating with super-hydrophobic properties. When the mass ratio of composite fillers and nano-SiO2 is 6.5:3.5, the water contact angle (WCA) of the coating can reach 150 degrees;, the sliding angle can reach 9 degrees, the infrared emissivity and the reflectivity of 1.06 mu m near-infrared light of the coating are 0.705 and 46.279 %, respectively. The coating has both good functional properties and superhydrophobic properties at the same time.