Aerosol-Assisted Atmospheric Cold Plasma Deposition and Characterization of Superhydrophobic Organic-Inorganic Nanocomposite Thin Films

A facile atmospheric pressure cold plasma process is presented to deposit a novel organic-inorganic hydrocarbon polymer/ZnO nanoparticles nanocomposite coating. Specifically, this method involves the utilization of an atmospheric pressure dielectric barrier discharge (DBD) fed with helium and the aerosol of a dispersion of oleate-capped ZnO nanoparticles (NPs) in n-octane. As assessed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-Fourier t ransform infrared (ATR-FTIR) spectroscopy, the deposited nanocomposite coating combines the chemical features of both the oleate-capped ZnO NPs and the polyethylene-like organic component originated from the plasma polymerization of n-octane. Additionally, scanning electron microscopy (SEM) and transmission scanning electron microscopy (TSEM) confirm the synthesis of hierarchical micro/nanostructured coatings containing quasi-spherical NPs agglomerates. The polyethylene-like polymer covers the NPs agglomerates to different extents and contributes to their immobilization in the three-dimensional network of the coating. The increase of both the deposition time (1-10 min) and the NPs concentration in the dispersion (0.5-5 wt %) has a significant effect on the chemical and morphological structure of the thin films and, in fact, results in the increase the ZnO NPs content, which ultimately leads to superhydrophobic surfaces (advancing and receding water contact angles higher than 160) with low hysteresis due to the hierarchical multiscale roughness of the coating.