Preparation of nano/micro-scale column-like topography on PDMS surfaces via vapor deposition: Dependence on volatility solvents

In this work, a column-like nano/micro-scale topography surface has been prepared via trichloro(octyl)silane (TCOS) vapor deposition on the air plasma oxidized polydimethylsiloxane (PDMSOx) surface. TCOS was mixed into n-heptyl alcohol and dimethyl-silicone oil to form a series of mixture. TCOS could anchor to the PDMSOx surface to form column-like nano/micro-scale topography while n-heptyl alcohol and TCOS volatilized to the PDMSOx surface in the subsequent vapor phase process. These surfaces were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared-attenuated total reflection, contact angle measuring system and atomic force microscopy. It was shown that TCOS had been successfully assembled on the polydimethylsiloxane surface. N-heptyl alcohol mixed into alkylsiloxane could regulate the scale and roughness of column-like nano/micro-scale topography.     

甲硅烷的分解复合的对称性

本文基于原子分子反应静力学证明甲硅烷SiH4的分解方式Ⅱ是对称性允许的,而分解方Ⅰ是对称性不许可的.     

Multi‐functional initiator and poly(carboxybetaine methacrylamides) for building biocompatible surfaces using “nitroxide mediated free radical polymerization” strategies

Biomaterials generally suffer from rapid nonspecific protein adsorption, which initiates many deleterious host responses, and complex chemistries that are employed to facilitate cellular interactions. A chemical approach that, based upon current literature, combines a nonfouling architecture with a biomemtic cell‐adhesive end‐group, is presented. Namely, surface‐initiated polymerization of zwitterionic [poly (carboxybetaine methacrylamide)] brushes, with controlled charge densities and phosphonate head groups. Nitroxide mediated free radical polymerization (NMFRP) was employed for various reasons: reduces presence of potentially cytotoxic organometallic catalysts common in atom transfer radical polymerization (ATRP); and it allows a phosphonate end‐group instead of the common brominated end‐group. Thermally oxidized silicon wafers were covalently functionalized with diethyl‐(1‐(N‐(1‐(3‐(trimethoxysilyl)propylcarbamoyl)ethoxy)‐N‐tert‐butylamino)ethyl)phosphonate. NMFRP was used to graft zwitterionic carboxybetaine methacrylamide monomers of varying inter‐charge separation. The resulting thin films were characterized using Attenuated Total Reflectance‐Fourier Transform Infrared (ATR‐FTIR) and X‐ray photoelectron (XPS) spectroscopy, ellipsometry, water contact angle analysis, and thermo gravimetric analysis (TGA). The effect of spacer group on the surface charge density was determined using zeta potential techniques. It is thought that this stratagem will facilitate the ability to tailor systematically both the interior and terminal polymer properties, providing a platform for further understanding how these conditions affect protein adsorption as well as cell‐surface interactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of organofunctional silanes with sterically hindered substituents at silicon atoms

Organofunctional silanes with more sterically hindered substituents at the silicon atom than the typical methoxy (ethoxy) group have lately been frequently used as silane coupling agents, in polymer coupling systems, sol‐gel processes and also as interpenetrating polymer network substrates. New and very efficient synthetic ways leading to organofunctional silanes of the above type with methacryl, amine, chloro and isocyanato functional groups are proposed here. Catalytic transesterification and/or alcoholysis of chloropropyltrialkoxysilanes followed by­nucleophilic substitution has been employed. Copyright © 2001 John Wiley & Sons, Ltd.     

Annealing effect in glass woven fabric composites,Part II. Bending properties

Effects of annealing on bending properties of composites reinforced with plain glass woven fabrics that were treated with different concentrations of silane coupling agent were investigated in this paper. Bending strength increased by annealing in the specimen treated with lower silane concentration. Higher annealing temperature in a range from 80°C to 150°C led to higher bending strength. Then, the fracture mode changed from a micro-crack type (low strength type) to a branched matrix crack type (high strength type) by annealing.     

Diastereoselective synthesis of substituted prolines via 5-endo-trig cyclisations of aza-[2,3]-Wittig sigmatropic rearrangement products

The major diastereoisomers of aza-[2,3]-Wittig sigmatropic rearrangement products from α-amino acid derivatives are susceptible to a rare nucleophilic 5-endo-trig cyclisations of an amine onto a non-conjugated vinylsilane in high yield and complete diastereocontrol. Five examples are presented, with cyclisation yields between 35 and 87%. A rationale for the stereoselectivity of the cyclisation is forwarded based upon the steric control factors that have been documented for the aza-[2,3]-Wittig sigmatropic rearrangement. A discussion of the mechanism in the context of the reaction conditions is also presented. Oxidation of the silyl group to a hydroxyl group and complete removal were demonstrated for synthetic utility.     

芳基硅烷、锗烷、锡烷的合成与表征

有机金属聚合物的研究近几年得到了很大的发展,含金属Ｓｉ、Ｇｅ、Ｓｎ的有机聚合物表现出特殊的导电性、非线性光学性等。我们合成了含Ｓｉ、Ｇｅ、Ｓｎ的有机金属聚合物的中间体芳基硅烷、锗烷、锡烷。合成路线如下:ａ:Ｒ=Ｍｅ,Ｍ=Ｓｉ;ｂ:Ｒ=Ｐｈ,Ｍ=Ｓｉ;ｃ:Ｒ=Ｐｈ,Ｍ=Ｇｅ;ｄ:Ｒ=Ｐｈ,Ｍ=Ｓｎ1　实验部分1 1　仪器和试剂原料均为化学纯,所有溶剂都经过严格的无水、无氧处理,所有反应均与Ｓｃｈｌｅｎｋ操作线连接;质谱:ＨＥＮＬＥＴＴＰＡＣＫＡＲＤＭＳ5989;1ＨＮＭＲ:ＢＲＵＫＥＲＡＣ80ＭＨｚ;熔点测量:ＬＥＩＴＺＢＩＯＭＥＤ…     

HIGH RESOLUTION SPECTROSCOPIC STUDY OF THE LOCAL MODE VIBRATIONAL STATES OF SILANE

The stretching vibrational overtone bands (3000), (4000) and (5000) of silane are recorded on a Fourier transform spectrometer with a specially made multipass cell at a resolution of 0.01 cm-1. The spectra show a striking symmetrical top rotational structure, which has been predicted as the limiting case of a spherical top exhibiting local mode behavior, and provides an excellent chance to study the local mode rotational structures in detail. This article reviews the interpretation and analysis of the spectra in both local mode and normal mode pictures. The intramolecular dynamics following initial single bond excitation is also discussed.