Surface Initiated Polymerization from Substrates of Low Initiator Density and Its Applications in Biosensors

Surface initiated polymerization (SIP) has become an attractive method for tailoring physical and chemical properties of surfaces for a broad range of applications. Most of those application relied on the merit of a high density coating. In this study we explored a long overlooked field of SIP. SIP from substrates of low initiator density. We combined ellipsometry with AFM to investigate the effect of initiatior density and polymerization time on the morphology of polymer coatings. In addition, we carefully adjusted the nanoscale separation of polymer chains to achieve a balance between nonfouling and immobilization capacities. We further tested the performance of those coating on various biosensors, such as quartz crystal microbalance, surface plasmon resonance, and protein microarrays. The optimized matrices enhanced the performance of those biosensors. This report shall encourage researches to explore new frontiers in SIP that go beyond polymer brushes.

Fast plasma sintering deposition of nano-structured silicon carbide coatings

Fast plasma sintering deposition of SiC nano-structured coatings was achieved using a specially designed non-transferred dc plasma torch operated at reduced pressure. Employing the Taguchi method, the deposition parameters were optimized and verified. With the optimized combination of deposition parameters, homogeneous SiC coatings were deposited on relatively large area substrates of Φ50 mm and 50×50 mm with a deposition rate as high as 20 μm/min. Ablation test showed that such coatings can be used as oxidation resistance coatings in high temperature oxidizing environment.

Solvent extraction of americium and europium ions by amide-derivatized polyethers from picric acid aqueous solution

The extraction of Am3+ and Eu3+ from picric acid aqueous solution by N,N-1,2-ethanediyl-bis[2-(N,N-diphenyl-carbamoyl-methoxy)-benzamide] was investigated by a radioactive tracer technique. The composition of the extracted species has been determined as ML(Pic)(3) (M = Eu, Am). The effect of various parameters such as pH, organic diluents, different extractants, picric acid concentration and extractants concentration on the extraction of Am3+ and Eu3+ has been studied. The extraction equilibrium mechanism has been also evaluated and discussed.

A study of low-energy ion induced radiolysis of thiol-containing amino acid cysteine in the solid and aqueous solution states

The radiolysis of cysteine under plasma discharge and irradiation of low-energy Ion beam was investigated. The damage of cysteine in aqueous solution under discharge was assessed via the acid ninhydrin reagent and the yield of cystine produced from the reaction was analyzed by FTIR In addition, the generation of hydrogen sulfide was also identified The destruction of solid cysteine under low-energy ion beam irradiation was estimated via monitoring IR bands of different functional groups (-SH, -NH3, -COO-) of cysteine. and the production of cystine from ion-irradiated solid cysteine after dissolution in water was also verified These results may help us to understand the inactivation of sulphydryl enzymes under direct and indirect interaction with the low-energy ion irradiation (C) 2010 Elsevier B V All rights reserved.

Trichloroisocyanuric acid: A convenient oxidation reagent for phase-transfer catalytic epoxidation of enones under non-aqueous conditions

Trichloroisocyanuric acid (TCCA) is a cheap, safe and readily available alternative to the commonly used hydrogen peroxide and hypochlorite for the phase-transfer catalytic epoxidation of alpha,beta-enones under non-aqueous conditions. A variety of chalcone derivatives give the corresponding epoxides with quantitative conversion and satisfactory yields in just a few hours under mild conditions. An asymmetric variant of the epoxidation can be carried out in the presence of chiral N-anthracenylmethylcinchonidine bromide catalyst giving 73-93% ees and 76-94% yields.

Polymeric fullerene oxide films produced by decomposition of hexanitro[60]fullerene

A new poly(fullerene oxide) thin film material has been fabricated by thermal activation and electron bombardment on hexanitro[60]fullerene (HNF) film deposited on a An substrate, all under vacuum conditions. The reaction products in the polymerization process are analyzed by XPS, UPS, IR, TGA-MS and LDI-MS techniques. It is found that the main effect of thermal and radiation treatments is to induce cleavage of -NO bonds from HNF molecules resulted in the release of nitric oxide gas and the formation of fullerene-bound oxyradicals, C-60-C-6. Spectroscopic evidence strongly suggests that rearrangement of fullerenic nitro moieties into nitrito groups is involved in the HNF decomposition process prior to the generation of reactive oxyradical intermediates. Consequently, the intermolecular coupling reaction of these oxyradicals leads to carbon polymer networks containing oxygen-bridged fullerenes. The thermally generated polymeric thin film is stable up to 900 K. Electron bombardment is also effective in both the decomposition of -NO2 groups and the removal of -OH groups present in HNF films. UV irradiation at 365 nm alone is shown to be not as efficient for the polymer formation. (C) 2003 Elsevier Ltd. All rights reserved.

Pd/C-catalyzed hydrodehalogenation of aromatic halides in aqueous solutions at room temperature under normal pressure

The hydrodehalogenation of aromatic halides, catalyzed by Pd/C in aqueous solutions, yields arenes in short reaction times at room temperature under normal pressure. The nature of the solvents has an important influence on the reaction rates and the activity of the catalyst. The catalyst shows the highest activity in water. In the hydrodechlorination of 4-chlorohypnone, it was in water that C-Cl bond was easier to be hydrogenated, and in isopropanol that C=O was easier to be hydrogenated. (C) 2004 Elsevier B.V. All rights reserved.