Large-Scale Fabrication of a Robust Superhydrophobic Thermal Energy Storage Sprayable Coating Based on Polymer Nanotubes

We propose a facile and effective route for large-scale fabrication of a superhydrophobic thermal energy storage (STES) sprayable coating with heat storage capacity and superhydrophobicity based on polydivinylbenzene (PDVB) nano-tubes (NTs). Herein, the STES coating was applied on wood by convenient spraying, and the PDVB NTs played an integral role in the STES coating. On the one hand, PDVB NTs act as a support material to adsorb and prevent the leakage of industrial paraffin wax (IPW) because of the lipophilicity of PDVB NTs and the capillary forces between the PDVB NTs and the melted IPW. By improving the specific surface area of PDVB NTs, the PDVB NTs show a great loading capacity for IPW (78.29 wt %), which contributes to the large latent heat of fusion (119.6 J/g) of the STES coating. Moreover, the STES coating possesses good thermal reliability and thermal energy conversion ability. On the other hand, PDVB NTs as a framework combine with fluorine-containing SiO2 nanoparticles to form a hierarchical structure of the STES coating, which endows the STES coating satisfactory water-repellent properties with a water contact angle of 157.7 degrees and a sliding angle of 1.3 degrees. In addition, the coating possesses outstanding resistance against corrosive liquids and UV irradiation as well as has self-cleaning properties. Surprisingly, the knife scratch test confirms that even if the surface of the STES coating is destroyed, the revealed surface will also present superhydrophobicity. Simultaneously, the STES coating has good adhesion strength that maintains excellent superhydrophobicity under ultrasonic treatment, finger rubbing, and severe friction due to the contribution of ethyl alpha-cyanoacrylate. Therefore, the STES coating has both great phase change behaviors and remarkable superhydrophobic properties to resist the erosion of the natural environment, which will pave the way for its application in practice.