PMMA films refractive index modulation via TiO2 nanoparticle inclusions and corona poling

The present study is focused on the characterization of optical properties of poly (methyl methacrylate) (PMMA) films and the possibilities of modulation and fine tuning of their refractive index by the inclusion of different concentrations of nano-sized titanium dioxide (TiO₂) particles (less than 33 nm) and corona poling. The samples are prepared by the “spin coating” method and they are charged in a conventional point-to-plain corona system. The transparent PMMA/TiO₂ films exhibit good optical properties in the visible range. An investigation of the film’s surface refractive index by two wavelengths laser refractometry utilizing the disappearing diffraction pattern method is carried out. The refractive index increases with increasing the TiO₂ content in the nanocomposite films. The corona poling increases the refractive index values for all samples regardless of the polarity and concentration of TiO₂ nanoparticles. The results show that the prepared nanocomposite films have a potential application for optical devices.