Synthesis and infrared emissivity properties of novel polyurethane/Ag/ZnO array composite coatings

A kind of novel ternary polyurethane (PU)/silver (Ag)/zinc oxide (ZnO) array composite coatings was fabricated by the growth of ZnO arrays onto the stainless steel substrates, the modification of Ag nanoparticles and following PU spinning. The structure, morphologies, wettability and mechanical properties of the PU/Ag/ZnO array composite coatings were measured by SEM, TEM, XRD, UV-vis, surface contact angle (CA) and nano indentation technology. The infrared emissivity values of the composites (8-14 mu m) were estimated. The results showed that hexagonal wurtzite ZnO arrays and face-centered cubic Ag nanoparticles were in the composite coatings with good dispersion. The content and the density of the Ag and ZnO arrays can be varied by controlling the deposition time of the Ag and the concentration of the ZnO crystal growth solution, which remarkably had effect on the surface roughness properties of the coatings. By comparison with PU, the mechanical properties of PU/Ag/ZnO array coatings were obviously improved. The PU/Ag/ZnO coatings exhibited improved infrared emissivity property than that of pure PU and PU/ZnO due to the introduction of component Ag with high reflectivity.