Browsing by Subject "Silicates"

Now showing 1 - 2 of 2

Open Access
Characterization of thermally poled germanosilicate thin films
(Optical Society of American (OSA), 2004) Ozean, A.; Digonnet, M.J.F.; Kino G.S.; Ay F.; Aydınlı, Atilla
We report measurements of the nonlinearity profile of thermally poled low-loss germanosilicate films deposited on fused-silica substrates by PECVD, of interest as potential electro-optic devices. The profiles of films grown and poled under various conditions all exhibit a sharp peak ∼0.5 μm beneath the anode surface, followed by a weaker pedestal of approximately constant amplitude down to a depth of 13-16 μm, without the sign reversal typical of poled undoped fused silica. These features suggest that during poling, the films significantly slow down the injection of positive ions into the structure. After local optimization, we demonstrate a record peak nonlinear coefficient of ∼1.6 pm/V, approximately twice as strong as the highest reliable value reported in thermally poled fused silica glass, a significant improvement that was qualitatively expected from the presence of Ge. ©2004 Optical Society of America.
Open Access
Preparation of fluorinated methacrylate/clay nanocomposite via in-situ polymerization: characterization, structure, and properties
(John Wiley and Sons Inc., 2016) Karamane, M.; Raihane, M.; Tasdelen, M. A.; Uyar, Tamer; Lahcini, M.; Ilsouk, M.; Yagci Y.
Novel fluorinated coating containing well-dispersed silicate nanolayers is successfully produced via in-situ free radical polymerization of 2,2,2-trifluoroethyl methacrylate in the presence of vinylbenzyl-functionalized montmorillonite with different loading. The organic modification of sodium montmorillonite is achieved through an ion exchange reaction with triphenylvinylbenzylphosphonium chloride as surfactant prepared before use by reaction with vinylbenyl chloride and phosphine. The following in-situ polymerization in the presence of organomodified clay leads to fluorinated nanocomposites with of partially exfoliated and intercalated morphologies, as determined via XRD and TEM analysis. The nanoscale dispersion of clay layers is also evidenced by thermal analysis; a moderate decrease of the glass transition temperature about 2–8 °C compared to their virgin PMATRIF and an improvement of their thermal stability as evidenced by TGA. The wettability of the nanocomposite films is also studied by contact angle measurements with water. The incorporation of organomodified clays not only increases the hydrophobicity of the fluorinated polymers but also improves the surface properties of obtained nanocomposites. Compared the virgin homopolymer, the mechanical properties of the nanocomposites are reduced by addition of organomodifed clay at temperature from 30 to 60 °C, whereas this trend is gradually decreased at higher temperature.