Organosilane polymers

Contact the substrate with the silane solution from 2 minutes to as long as 1 hour, depending on the degree of organosilane polymer deposition desired on the surface. Optimization of the reaction time should be done to determine the best performance of the modified substrate in its intended application. 

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... 

Table I. Yields and Molecular Weights (Relative to Polystyrene) for Both Fractions of the Bimodal Distribution from Gel Permeation Chromatography in THF of Organosilane Polymers.

In 1983, Wolford et al. (5) discovered a new type of hydrogenated amorphous silicon, called polysilane alloys, which include a large number of silicon hydride polymers. Their structures were studied by Matsumoto et al. (6), and it was clarified that polysilane alloys are materials with intermediate properties relative to those of amorphous silicon and organosilane polymers. 

Figure 1. Si-backbone materials (a) crystalline silicon, (b) amorphous hydrogenated silicon, (c) poly silane alloy, and (d) organosilane polymer.

A. Condensation Routes to Main Chain Ferrocene-Organosilane Polymers... 

Condensation approaches to ferrocene/organosilane polymers have been extended to the synthesis of low molecular weight materials 11 (jc = 6, R = Me) with M 3500 from the reaction of dilithioferrocene-tmeda with the dichlorohexasilane Cl(SiMe2)6Cl (39). These polymers were shown to possess electrical conductivities in the range of 10" -10 S/cm... 

J. P. Wesson, T. C. Williams, Organosilane Polymers. I. Poly(dimethylsilylene), Tech. Rept. Contract No. N00014-75-C-1024, ADA050 337/5ST, 1977. 

Substituted poly(organosilanes) [-SiRR -] have recently become the focus of intense scientific and commercial interest, and synthetic efforts have been successful in obtaining high molecular weight organosilane polymers and copolymers containing both alkyl and aryl substituents. 

In 1995, Natan et al. reported that Au and Ag nanoparticles adsorbed onto an organosilane-polymer-modified Si substrate could be used as a SERS-active substrate [97]. Subsequently, in 2001 the same authors [98] proposed a novel approach based on the self-assembled monolayer technique which allows the preparation of regularly arranged monodispersed colloidal Au and Ag nanoparticles on functionalized metal or glass substrates. It is now possible to synthesize or fabricate metal nanostructures of various shapes and sizes with a narrow size distribution. Nanoparticles assembled on an electrically conductive substrate can significantly improve the surface uniformity of the EC-SERS substrate. Therefore, use of nanoparticle sols or assembled nanoparticles as SERS substrates has expanded very rapidly during recent years [92]. 

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