Molecular Composites Comprising TiO₂ and Their Optical Properties

Abstract

An in situ synthesis to form an organic-inorganic hybrid film with tunable optical properties is described. The nanocomposite comprises a titania nanophase that is formed from titanium alkoxide in the presence of a matrix polymer. XPS study indicates that titanium (Ti) in the nanophase is fully oxidized to Ti(IV), similar to that in TiO 2 . When a random copolymer, of styrene and 3-methacryloxypropyltrimethoxysilane (MPTMS), comprising functional groups that form a covalent bond with the in situ synthesized TiO 2 is used, TEM and AFM show no phase contrast between the organic and inorganic phases at the nanometer level. This suggests a molecular level mixing of the polymer and formed inorganics and thus the formation of a molecular composite. This synthesis generates transparent composite films with any level of incorporation of TiO 2 . The refractive indices of these molecular composite films are much higher than that predicted on the basis of effective medium theories; e.g., at a TiO 2 loading of 27 vol %, the resulting molecular composite film exhibits a measured refractive index of 1.76 compared to that of 1.66 predicted by effective medium theories.

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

“…It can be seen from Fig. 6 that the refractive [17,19,20]. The regression value is 0.97 as exhibited in Fig.…”

Tailoring the optical and thermomechanical properties of polymer host–guest systems

“…12,13 The in situ synthesis of organic-inorganic hybrid thin films exploiting the titania nanophase formation by the sol-gel reaction of titanium alkoxide in the presence of a polymer host enables large titania loads accompanied by a high n increase and good transmittance values for film thicknesses in the micrometer and submicrometer range. 14,15 Transparent composites containing BaTiO 3 as a high-n filler were described in ref. 16 .…”

Nanofluids: Stability, phase diagram, rheology and applications

“…Their shapes may be spheres, discs or rods. The study of nanofluids is an important branch of nanotechnology, since it has potential applications in transportation and electronics cooling (Buongiorno et al, 2009;Eastman, Choi, Li, Yu, & Thompson, 2001;Godson, Raja, Mohan Lal, & Wongwises, 2010;Shalkevich, Shalkevich, & Bürgi, 2010;Wang & Mujumdar, 2007;Wu et al, 2010), biomedicine (Ai et al, 2005;Grainger & Castner, 2008;Ma & Liu, 2007;Nasongkla et al, 2006;Xu, Li, Li, Feng, & Gao, 2009), oil drilling (Ju, Fan, & Ma, 2006), nano-structure fabrication (Ai et al, 2005;Choi & Alivisatos, 2010;DeVries et al, 2007;Kane, Inan, & Saraf, 2010;Nasongkla et al, 2006;Rao et al, 2009;Tam et al, 2010) and nanocomposites (Rao & Chen, 2008;Guo, Han, Li, & Zhao, 2010;Lu, Liu, & Lee, 2005). Its fundamental science spans colloidal science, surface chemistry, fluid mechanics and materials science.…”