Polymer-titania material

BHO 10] Bhongale C.J., Thelakkat M., Efficient hybrid polymer/titania solar cells sensitized with carboxylated polymer dye , Solar Energy Materials and Solar Cells, vol. 94, no. 5, pp. 817-822, 2010. 

By using a similar procedure for the preparation of hybrids of silica, hybrids materials consisting of other metal oxides were also prepared by the group of Wilkes [15]. For example, titania was incorporated into organic polymers by using the chemically controlled condensation (CCC) method for the preparation of poly(tetramethylene oxide)-silica or poly(dimethylsiloxane)-silica hybrids. Especially, in the case of the hybrid with poly (tetramethylene oxide), the modulus or ultimate strength of the hybrid increased in the presence of titania component, as shown in Table 3. This phenomenon was explained by the catalytic ability of... 

As an alternative, stable high-coverage nonpolar RPC sorbents phases have been prepared by cross-linking hydrophobic polymers at the silica surface, either via free radical 143 or condensation 101 polymerization chemistry. In this case, the underlying silica becomes partly protected from hydrolytic degradation due to the presence of the hydrophobic polymer film coating that effectively shields the support material. Similar procedures have been employed to chemically modify the surface of other support materials, such as porous zirconia, titania, or alumina, to further impart resistance to degradation when alkaline mobile-phase conditions are employed. Porous polystyrene-divinylbenzene sorbents, be-... 

The monoliths are prepared both from organic (mainly based not only on polystyrene, acrylamides, acrylates, or methacrylates but also on imprinted polymers) and inorganic materials (based on sUica, zirconia, titania, or aluminium oxide) as continuous... 

Several polymer/polyelectrolyte-nanocrystal hybrid devices have been fabricated seeking to exploit the electro and photoluminescent properties of such material [179-188]. Device fabrication in all these cases is by low-cost self-assembly based techniques. These devices utilize thin films of these hybrids obtained either by multilayer deposition or drop/spin casting methods. Thus, solar cells have been made from poly(2-hexylthiophene)-CdSe nanorod multilayers, lasers from drop cast films of CdSe-titania composites and an infrared emitter from multilayers... 

Ordered macroporous materials with pore sizes in the sub-micrometer range have applications in low-dielectric-constant materials and lightweight structural materials. Macroporous oxides such as silica, titania, and zirconia as well as polymers with well defined pore sizes in the sub-micrometer regime have been successfully synthesized.[166,167]... 

Dopants also influence the emission processes from PPVs. Improved red dopants have been based on pyran dyes" while Qo doping appears to be variable" "". Doping with electron transport materials such as oxadiazoles give polymers with balanced properties for hole transport". The avoidance of low molecular weight material in the synthesis of cyano based PPVs is important" as are head to head and tail to tail chain sequences in thiophene based polymers. Head to tail tetramer sequences were the most fluorescent. Metal ion doped PPV s are claimed to be good chemosensors and broad emission is observed from titania doped PPV . Electron rich dopants enhance the emission in the red region while electro and photoinduced infrared bands from PPV are similar . ... 

The presence of titania on Cr/silica also has a strong and beneficial effect on the polymer s MW distribution. Titania tends to broaden the MW distribution by contributing large amounts of low-MW material, which, as already noted, tends to lower the overall average MW. An example is shown in Figure 99. The addition of titania generates a new class of active sites that terminate chains easily and thus produce mainly low-MW polymer. 

The sites producing low-MW polymer on silica-titania seem to be more stable than those generated from other materials, and this tendency continues to make titania the preferred additive for commercial MI enhancement. The reason for this behavior is not entirely clear. Ti ions may fit into the silica lattice more easily than many other ions. Titanium applied to Cr/alumina catalysts does not produce the same effect on MI potential. 

It is well established that the presence of fluoride on a Cr/silica-titania catalyst increases its 1-hexene incorporation efficiency, and lowers the amount of very low-MW material [605]. Table 43 shows one example of this. Two catalysts, Cr/silica and Cr/silica-titania, were activated at 600 °C, with and without fluoride. These catalysts were tested for polymerization activity in the presence of 0.5 mol L 11-hexene. In the absence of titania, no difference was observed in the amount of 1-hexene incorporated into the polymer. However, Cr/silica-titania exhibited a major increase in 1-hexene incorporation when it contained fluoride. 

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