Silicon containing spacers

Silicon-Containing Spacers for the Synthesis of Tin-Containing Multidentate Lewis Acids... 

Control of Distannoxane Structure by Silicon-Containing Spacers... 

These preliminary results show that the silicon-containing spacers play an essential role in controlling the structure of the distannoxane dimers 7,8a, and 8b. 

In another report, a fluid filter was constructed using two silicon membranes (containing numerous 10- im-diameter holes). The two membranes were displaced laterally relative to each other and separated by a distance with silicon dioxide spacers of submicron thickness [827],... 

In search for systems which could meet these requirements we investigate the potential of silicon-contaiiiing spacers for the syntheses of new tin-containing multidentate Lewis acidic macrocycles and report here preliminary results of our studies. 

Hadziioannou et al. introduced a dialkylsilyl spacer between PPV-like segments [123] via Heck reaction (Scheme 45), where R is an alkoxy or an alkyl group. For a=, the polymer can be obtained via Wittig reaction between the silicon containing dialdehyde and the appropriate triphenylphosphonium halide [124]. 

Another type of linear silicon-containing thiophene oUgomers are monochlorosi-lyl derivatives of dialkyloligothiophenes Cl-Si-Spacer-OligoT-End (Fig. 4) [23,24]. 

In general, these organomodified trisiloxanes are based on a common structural principle They consist of a lyophobic silicone backbone containing an alkyl spacer group connected by a silicon-carbon bond. The hydrophilic moiety, which can be either ionic or nonionic, is attached to the alkyl spacer... 

The surface of the model is covered with a uniform layer of clay or plasticine. The thickness of the spacing layer determines the thickness of the final mold. The next step is to build up a rigid layer on top of the spacer. This support is either poured (plaster or casting resin) or built up in layers by spreading the material (polyester, polyurethane or epoxy resin reinforced with fiberglass matting). Once the support has set, it is separated from the spacer, which is then discarded. The support, which must contain air-escape and feeding holes, is now fitted over the model. The silicone rubber is poured into the hollow space between the support and the model and allowed to cure. The... 

The idea of control over polymerization rate in a stirred-vessel FRRPP system has been extended to dimensional control of a quiescent polymerization film material. Polymerization was initiated in certain specific regions by directed radiation, similar to methods used in microlithography in microsystems. In a number of efforts, synchrotron X-ray was used as the radiation source and a 500-p.m thick photomask made of gold was employed (Tirumala 2003 Tirumala et al., 2003, 2004a,b,c, 2005a,b, 2006). Liquid reactive material containing monomer(s) and sol-vent/precipitant were sandwiched between two standard 8-in. Silicon wafers with a thin spacer material (Fig. 4.7.1). Heat is applied on the backside of the wafer system through a heater block of controlled temperature. 

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