Siloxane

About: Siloxane is a research topic. Over the lifetime, 11269 publications have been published within this topic receiving 142665 citations.

The chemistry of organic silicon compounds

Abstract: Historical overview and comparison of silicon with carbon, J.Y.Corey theoretical aspects of organosilicon compounds, Y.Apeloig structural chemistry of organic silicon compounds, W.S.Sheldrick dynamic stereochemistry at silicon, R.J.P.Corriu et al thermochemistry, R.Walsh analysis of organosilicon compounds, T.R.C.Crompton positive and negative ion chemistry of silicon-containing molecules in the gas phase, H.Schwarz NMR spectroscopy of organosilicon compounds, E.A.Williams photoelectron spectra of silicon compounds, H.Bock and B.Solouki general synthetic pathways to organosilicon compounds, L.Birkofer and O.Stuhl recent synthetic application of organosilanes, G.L.Larson acidity, basicity and complex formation of organosilicon compounds, A.R.Bassindale and P.G.Taylor reaction mechanisms of nucleophilic attacks at silicon, A.R.Bassindale and P.G.Taylor activating and directive effects of silicon, A.R.Bassindale and P.G.Taylor the photochemistry of organosilicon compounds, A.G.Brook trivalent silyl ions, J.B.Lambert and W.J.Schulz Jr multiple bonds to silicon, G.Raabe and J.Michl bio-organic chemistry, R.Tacke and J.Linoh polysilanes, R.West hypervalent silicon compounds, R.J.P.Corriu and J.C.Young siloxane polymers and copolymers, T.C.Kendrick organosilicon derivatives of phosphorus arsenic, antimony and bismuth, D.A.Armitage chemistry of compounds with silicon-sulphur, silicon-selenium and silicon-tellurium bonds, D.A.Armitage transition-metal silyl derivatives, T.D.Tilley the hydrosilylation reaction, I.Ojima.

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots†

Abstract: We describe the synthesis of water-soluble semiconductor nanoparticles and discuss and characterize their properties. Hydrophobic CdSe/ZnS core/shell nanocrystals with a core size between 2 and 5 nm are embedded in a siloxane shell and functionalized with thiol and/or amine groups. Structural characterization by AFM indicates that the siloxane shell is 1−5 nm thick, yielding final particle sizes of 6−17 nm, depending on the initial CdSe core size. The silica coating does not significantly modify the optical properties of the nanocrystals. Their fluorescence emission is about 32−35 nm fwhm and can be tuned from blue to red with quantum yields up to 18%, mainly determined by the quantum yield of the underlying CdSe/ZnS nanocrystals. Silanized nanocrystals exhibit enhanced photochemical stability over organic fluorophores. They also display high stability in buffers at physiological conditions (>150 mM NaCl). The introduction of functionalized groups onto the siloxane surface would permit the conjugation of ...

Platinum complexes of unsaturated siloxanes and platinum containing organopolysiloxanes

Abstract: PLATINUM COMPLEXES OF UNSATURATED SILOXANES ARE PROVIDED WHICH ARE USEFUL AS HYDROSILATION CATALYSTS. THESE PLATINUM-SILOXANE COMPLEXES MUST CONTAIN LESS THAN ABOUT 0.1 GRAM ATOM OF HALOGEN, PER GRAM ATOM OF PLATINUM, AND PREFERABLY SUBSTANTIALLY FREE OF HALOGEN WHICH INCLUDE PLATINUM-SILOXANE COMPLEXES WHICH ARE SUBSTANTIALLY FREE OF INORGANIC HALOGEN. THESE PLATINUM-SILOXANE COMPLEXES CAN BE MADE BY EFFECTING CONTACT BETWEEN A PLATINUM HALIDE AND AN UNSATURATED SILOXANE, FOR EXAMPLE, 1,3-DIVINYLTETRAMETHYLDISILOXANE, AND REMOVING AVAILABLE INORGANIC HALOGEN FROM THE RESULTING MATERIAL. IN ADDITION, CURABLE ORGANOPOLYSILOXANE COMPOSITIONS ARE PROVIDED COMPRISING AN ORGANOPOLYSILOXANE POLYMER AND AN EFFECTIVE AMOUNT OF SUCH PLATINUM-SILOXANE COMPLEX.

Studies on surface wettability of poly(dimethyl) siloxane (PDMS) and glass under oxygen-plasma treatment and correlation with bond strength

Abstract: An issue in microfabrication of the fluidic channels in glass/poly (dimethyl siloxane) (PDMS) is the absence of a well-defined study of the bonding strength between the surfaces making up these channels. Although most of the research papers mention the use of oxygen plasma for developing chemical (siloxane) bonds between the participating surfaces, yet they only define a certain set of parameters, tailored to a specific setup. An important requirement of all the microfluidics/biosensors industry is the development of a general regime, which defines a systematic method of gauging the bond strength between the participating surfaces in advance by correlation to a common parameter. This enhances the reliability of the devices and also gives a structured approach to its future large-scale manufacturing. In this paper, we explore the possibility of the existence of a common scale, which can be used to gauge bond strength between various surfaces. We find that the changes in wettability of surfaces owing to various levels of plasma exposure can be a useful parameter to gauge the bond strength. We obtained a good correlation between contact angle of deionized water (a direct measure of wettability) on the PDMS and glass surfaces based on various dosages or oxygen plasma treatment. The exposure was done first in an inductively coupled high-density (ICP) plasma system and then in plasma enhanced chemical vapor deposition (PECVD) system. This was followed by the measurement of bond strength by use or the standardized blister test.

Silicatein filaments and subunits from a marine sponge direct the polymerization of silica and silicones in vitro

Abstract: Nanoscale control of the polymerization of silicon and oxygen determines the structures and properties of a wide range of siloxane-based materials, including glasses, ceramics, mesoporous molecular sieves and catalysts, elastomers, resins, insulators, optical coatings, and photoluminescent polymers. In contrast to anthropogenic and geological syntheses of these materials that require extremes of temperature, pressure, or pH, living systems produce a remarkable diversity of nanostructured silicates at ambient temperatures and pressures and at near-neutral pH. We show here that the protein filaments and their constituent subunits comprising the axial cores of silica spicules in a marine sponge chemically and spatially direct the polymerization of silica and silicone polymer networks from the corresponding alkoxide substrates in vitro, under conditions in which such syntheses otherwise require either an acid or base catalyst. Homology of the principal protein to the well known enzyme cathepsin L points to a possible reaction mechanism that is supported by recent site-directed mutagenesis experiments. The catalytic activity of the “silicatein” (silica protein) molecule suggests new routes to the synthesis of silicon-based materials.