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The monoclinic phase vanadium dioxide VO2 (M) based transparent thermochromic smart films were firstly fabricated through heat treatment of opaque VO2-based composite nanofibrous mats, which were deposited on the glass substrate via electrospinning technique. Noteworthily, the anti-oxidation property of VO2 smart film was improved due to inner distribution of VO2 in the polymethylmethacrylate (PMMA) nanofibers, and the composite mats having water contact angle of 165° determined itself good superhydrophobic property. Besides, PMMA nanofibrous mats with different polymer concentrations demonstrated changeable morphology and fiber diameter. The VO2 nanoparticles having diameter of 30–50 nm gathered and exhibited ellipse-like or belt-like structure. Additionally, the solar modulation ability of PMMA-VO2 composite smart film was 6.88% according to UV–Vis-NIR spectra. The research offered a new notion for fabricating transparent VO2 thermochromic material.

Polytetrafluoroethylene (PTFE) film has been deposited on solar selective absorber (SSA) by electron beam evaporation. The water contact angle of the SSA surface after coating with PTFE (called PSSA) has increased from 72° to 150°, indicating that the surface has changed from hydrophilic to superhydrophobic. The absorptance of the SSA was 92.91% after coating with PTFE, while the emittance of the SSA was slightly increased due to the absorption of PTFE material itself. The color difference of SSA before and after coating with PTFE was small because of the high transmittance of PTFE film. In addition, the self-cleaning tests via water droplets of SSA and PSSA show that SSA has significant self-cleaning property after coating with PTFE. The results can provide reference for superhydrophobic coating applied to solar thermal fields.

In this work, a complete process for preparation of SiO2/Cs0.32WO3 composite coatings with superhydrophobic and NIR shielding properties has been proposed. Combined nano-porous SiO2 with the spectral selective Cs0.32WO3, the composite coating could not only show excellent heat blocking property but also possess self-cleaning performance. In the simulated contaminant experiment, almost all of dust particles on the surface of composite coating could be picked up by the rolling droplets, and the water contact angle of the coating was up to 160°. The thermal shielding experiment proved that the SiO2/Cs0.32WO3 composite coating could effectively reduce more than 20% room temperature in the same irradiation time. Furthermore, the energy consumption simulation shows that comparing with normal glass, the SiO2/Cs0.32WO3 coated glass could save about 15.9% total electrical consumption per year in Guangzhou, which is even superior with that of low-e glass.