Facile preparation of infrared-transparent, superhydrophobic coatings for infrared detection and personal thermal management

Capturing thermal radiation using highly infrared (IR)-transparent materials have drawn great attention for diverse applications, such as IR guidance, IR detection, thermal radiation imaging, radiative cooling etc. However, the previously reported IR-transparent materials have the bottleneck of lacking superhydrophobicity, resulting in the degradation due to the dust, fog, rain, frost outdoors. Here, a durable IR-transparent superhydrophobic coating is reported via the spraying of polyester (PE) microspheres and fluorinated ZnS nanoparticles (NPs). Due to the high transmittance of ZnS and PE, the coating shows excellent IR transparency (around 90 %) in 8 ∼ 14 μm thermal IR band. Benefitting from the robustness of 3D connected PE network, the coating maintains superhydrophobicity after 180 cycles of linear wearing under 6 kPa. Moreover, the water jetting/atomizing/dust tests indicate that this coating effectively ensures the high accuracy of IR imaging lens under rainy/foggy/dusty environments. This coating on fabrics also achieves a remarkable radiative cooling effect for outdoor conditions to keep human body comfortable. With its facile preparation and versatile features, this coating has great potential on IR window, IR imaging and personal thermal management.