We investigated the properties of organic-inorganic hybrid coating films prepared by a sol-gel reaction using a nanosized boehmite sols. The sol was synthesized as a protective coating, functional coating, binder, etc. The sol was prepared from spherically shaped boehmite, and a mixture of spherical and fibrous shaped boehmite. Sol solutions were used to deposit onto substrates by way of a dip-coating process. In order to investigate the surface hydrophobicity, roughness and transmittance of coating films, a contact angle meter, a surface profiler and a UV-Vis spectrophotometer were used. In addition, surface modification of boehmite was investigated by a FT-IR spectrometer. Contact angle and surface roughness of coating films gradually increased with increasing reaction time due to the gelation of the sol by successive condensation reactions. The transmission rate of coating films within the visible-wavelength region was greater than 90% when the reaction time was less than 48 h. FT-IR measurement showed the spectra of condensation of MTMS and boehmite.

Keywords: Coating films, Sol-gel, Boehmite, Infrared spectroscopy, Surface properties