Fabrication and characterization of GRIN plastic rods containing silver nanoparticles with novel surfmers

Both novel polymerizable surfactants of 2-(methacroyloxy)ethyl succinate (MAES) and succinic acid mono{11-[2-(2-methylacryloyloxy)ethoxy]undecyl} ester (SAME-11) were synthesized in this investigation. A novel method was also developed for the preparation of gradient refractive index (GRIN) plastic rods containing inorganic nanoparticles with the polymerizable surfactants (surfmers). Silver nanoparticles were prepared using W/O (water in oil) reverse micelle technique in the presence of the surfmers. The effect of w values (w = [H₂O]/[surfmer]), silver nitrate concentration, surfmer/isooctane/ H₂O ratio, and initiator concentration on the nanoparticle size was investigated. The optical absorption spectra of the micellar samples were recorded on a speetrophotometer at room temperature in the range of 200-900 nm. The nanoparticle size was confirmed with a transmission electron microcopy (TEM) technique. To introduce the nanoparticles into the GRIN plastic rods, methyl methacrylate (MMA) was used instead of isooctane in the organic phase. Nanoparticles were found to increase the refractive index of plastic rods effectively. Light scattering and an opaque appearance due to the aggregation of nanoparticles and the existence of surfactants were solved using the polymerizable surfmers in this investigation. We estimated both the real image transmission and the three dimensional refractive index distributions of the prepared GRIN plastic rods. The results of this investigation suggested that nanoparticles could be used as a kind of dopant to fabricate GRIN plastic rods and increased its refractive index effectively. Polymerizable surfactant could further raise the refractive index of the core of the GRIN rods leading to an increase of the numerical apertures (NA) and the acceptance angle (θ_max) of the plastic rods.