排序方式: 共有17条查询结果,搜索用时 15 毫秒
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Kyoko Shimizu Frances Helen Blaikie Mikkel Kongsfelt Kristian Damgaard Schøler Sørensen Steen Uttrup Pedersen Kim Daasbjerg 《Journal of polymer science. Part A, Polymer chemistry》2016,54(1):91-98
A simple electrochemical approach based on potential sweeping has been developed for growing poly(phenylene sulfide) (PPS) brushes from 4,4’‐disulfanediyldibenzenediazonium salt on glassy carbon and stainless steel. First, the diazonium salt becomes reduced at the substrate on the initial part of the sweep carried out in a negative direction to form a covalently bonded diphenyl disulfide film. Once sufficiently extreme potentials are reached the disulfide bridges are reductively cleaved to form a thin layer of covalently attached thiophenolates. These are prone to be involved in fast coupling reactions with the diazonium salt to form PPS brushes in a repetitive growth process. In this manner linear PPS brushes with thicknesses up to 150 nm are easily formed. In addition, exact control on the brush length may be exerted through the switching potential selected or the number of sweeps applied. The films are characterized by time‐of‐flight secondary ion mass spectrometry which shows that the film growth is accompanied by an increase in the intensity ratio of S?/ in line with the proposed PPS structure. This structure was further supported by Raman spectra, exhibiting a high‐intensity C?S stretch band and no S?S stretch band. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 91–98 相似文献
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Bell CL van Helden JP Blaikie TP Hancock G van Leeuwen NJ Peverall R Ritchie GA 《The journal of physical chemistry. A》2012,116(21):5090-5099
Accurate measurements of the absolute concentrations of radical species present in the atmosphere are invaluable for better understanding atmospheric processes and their impact on Earth systems. One of the most interesting species is HO(2), the hydroperoxyl radical, whose atmospheric daytime levels are on the order of 10 ppt and whose observation therefore requires very sensitive detection techniques. In this work, we demonstrate the first steps toward the application of external-cavity diode-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) to the detection of the HO(2) radical in the near-infrared range. Measurements of stable species and of HO(2) were made in a laboratory setting, and the possibilities of extending the sensitivity of the technique to atmospheric conditions are discussed. 相似文献
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Atomic clusters have been deposited between lithographically defined contacts with nanometer scale separations. The design of the contacts is based on an appropriate application of percolation theory to conduction in cluster deposited devices and allows finite-size effects to be clearly observed. It is demonstrated, both by experiment and by simulation, that for small contact separations the percolation threshold is shifted to extremely low surface coverages. The selected rectangular contact geometry ensures that wirelike structures are formed close to the percolation threshold. 相似文献
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M. Schulze S. Gourley S. A. Brown A. Dunbar J. Partridge R. J. Blaikie 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):291-294
A range of percolating atomic cluster films, with
nanoscale overall dimensions, have been studied using a
combination of in situ and
ex situ electrical transport
measurements, together with field emission electron microscopy
and atomic force microscopy. Bismuth clusters with mean diameter
20 nm were deposited between electrical contacts defined by
electron beam lithography. The morphology of the films can be
understood within percolation theory, and the electrical
measurements show complex behaviour characteristic of both
percolation effects and modification of the cluster films by
current flow and by oxidation. 相似文献
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