Surface Modification and Functionalization of Oxide Nanoparticles for Superhydrophobic Applications

Abstract

Oxide nanoparticles have tremendous technological applications in the present days in diverse fields. In this study, the surface modification and functionalization of hydrophilic silica (SiO2) and zinc oxide (ZnO) nanoparticles were performed to obtain superhydrophobicity. Monodispersive nanoparticles of SiO2were prepared by Stöber process using tetraethoxysilane (Si (OC2H5)4) as a precursor and ammonium hydroxide as a catalyst in a ethanolic solution. The surface modification of the silica nanoparticles were performed using fluoroalkylsilane (FAS-17: C16H19F17O3Si) molecules to obtain fluorinated silica nanoparticles of diameter varying from 50nm to 300nm. On the other hand, surface modification of zinc oxide (ZnO) nanoparticles was performed using stearic acid (C18H36O2) molecules to obtain methylated ZnO nanoparticles. These functionalized nanoparticles were characterized both in the form of powder as well as thin films. The bonding characteristics of FAS-17 molecules with SiO2and stearic acid molecules with ZnO were investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Nanostructured thin films of these functionalized oxide nanoparticles exhibit superhydrophobicity with contact angles over 150° with water roll-off properties. Such functionalized oxides nanoparticles, therefore, can be easily incorporated in coatings and paints for various applications in emerging technologies like biomedical applications, anti-corrosion, anti-icing, drag reduction and energy consumption reduction.