Silicon-Containing Aromatic Polymers

These materials have the potential of being stable at high temperatures. One typical preparatory procedure consists of condensing bisphenols with suitable silicon derivatives [227]  

Many of these polymers are soluble and exhibit good heat stability. An example is one such material prepared by this procedure and shown below  

The starting materials can also be silanols, as for instance in a synthesis of polycarbonates [227]. Preformed bis-silanols are used in this particular example  

One publication describes syntheses of copolyesters and copolyamides that contain phenoxalin rings [228]  

7 Step-Growth Polymerization and Step-Growth Polymers 

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The use of silicon-containing phenolic polymers with NDS compounds present as the photoactive polarity switch has been investigated. Formaldehyde condensation polymers with m-trimethyl-silylphenol (19) have been prepared. It is necessary to incorporate phenol as a comonomer in order to decrease the hydrophobicity of these resins so that they are soluble in aqueous base. The maximum silicon content obtainable is around 9% due to the acidolysis of the aromatic carbon-silicon bond during the acid-catalyzed polymerization process. Nevertheless, high resolution images with good oxygen etch resistance are obtained when these resins are formulated into resists with NDS derivatives present. 

Many substituted polyacetylenes (e.g., all the polymers in Table 25) are completely soluble in low-polarity solvents such as toluene and chloroform. Their solubility can be attributed to the presence of substituents and their amorphous structure. When inspected in more detail, aliphatic and silicon-containing polyacetylenes are soluble in aliphatic solvents such as hexane but insoluble in 1,2-dichloroethane, whereas aromatic polyacetylenes show the opposite solubility property. 

In order to improve the solubility of aromatic polymers silicon-containing polymers have also been synthesized, by introduction of siloxane or silarylene linkages into polymer backbones such as polyamides, polybenzimidazoles and polyimides [50]. The resultant polymers show fair solubility in organic solvents but most of them have poorer thermal stability then their analogues without siloxane or silarylene linkages. 

Given that the absorption phenomenon at EUV is atomic, almost every element is opaque at EUV (see Eig. 14.22) except thin films of polymers with high carbon content (as in aromatic polymers based on PHOST) and silicon (see Fig. 14.23). Polymers containing high amounts of oxygen and fluorine have very high absorptivity at EUV (see Fig. 14.23). 

A second series of LARC-13 adhesives was synthesized containing aromatic amine-terminated silicone elastomers of varying chain lengths. Changing the elastomer repeat unit from n = 10 to n = 105 had very little effect on polymer properties. However when a 50 50 combination of long and short-chained elastomers were reacted into the LARC-13 amic acid, adhesive strengths were enhanced. A concentration of 15% by weight of elastomers was found to maximize adhesive properties for this system. 

Our ongoing strategy to develop new fluorosilicone materials has been to combine the well known preparative chemistry of silicon containing compounds with the relatively new development of perfluorocyclobutane (PFCB) aromatic ether polymers. PFCB materials are prepared by the thermal cyclodimerization of trifluorovinyl ether (TFVE) monomers." " Recently we developed a synthetic... 

Organopolysilanes (i.e., high molecular weight polymers which contain only silicon in the backbone) are old materials which have renewed interest because of improvements in synthetic and characterization techniques. The first reported aromatic organosilane polymers were described by Kipping in 1924... 

The incorporation of siloles in polymers is of interest and importance in chemistry and functionalities. Some optoelectronic properties, impossible to obtain in silole small molecules, may be realized with silole-containing polymers (SCPs). The first synthesis of SCPs was reported in 1992.21 Since then, different types of SCPs, such as main chain type 7r-conjugated SCPs catenated through the aromatic carbon of a silole, main chain type cr-conjugated SCPs catenated through the silicon atom of a silole, SCPs with silole pendants, and hyperbranched or dendritic SCPs (Fig. 2), have been synthesized.10 In this chapter, the functionalities of SCPs, such as band gap, photoluminescence, electroluminescence, bulk-heterojunction solar cells, field effect transistors, aggregation-induced emission, chemosensors, conductivity, and optical limiting, are summarized. 

The design of single-component polymer transport materials continues to interest researchers in this field. The use of such materials will completely eliminate solvent extraction, diffusional instability, and crystallization of the small molecules. One obvious route that has not been successful to date is the design of yet another aromatic-amine-containing carbon-backbone polymer. An alternative may be to explore the large class of glassy silicon-backbone polymers, such as polysilylenes (14) and polyphosphazenes (iS). 

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