Study of a zinc chloride in poly(ethylene glycol) layer on an aluminium oxide surface by inelastic electron tunneling spectroscopy

Line, M. J.; Pritchard, R. G.; Pynenburg, R.; Latham, R. J.; Linford, R. G.

doi:10.1002/sia.740230717

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…Hence, the partition behavior of silicon dioxide is determined by the relative strength of the PEG/SiO 2 and Dex/SiO 2 interactions. From the above discussion, it appears that PEG interacts more strongly with silica surface than dextran, because the adsorption of PEG on surface shows high affinity (27)(28)(29)(30)(31)(32)(33)(34) while the polysaccharide only shows an adsorption process with poor affinity (38)(39)(40)(41). This is the reason why silica prefers the PEG-rich phase at low pH values.…”

Section: Effect Of Ph On Silica Partition In the Peg/dextran Systemmentioning

confidence: 98%

“…It is known that PEG adsorbs on silica surface through hydrogen bonding between the H atom of the Si-OH group and the O atom in the PEG chain, and it is a typical polymer adsorption with high affinity (27)(28)(29)(30)(31)(32)(33)(34). The neutral Si-OH sites favor the adsorption of PEG (29,(31)(32)(33).…”

Section: Effect Of Ph On Silica Partition In the Peg/dextran Systemmentioning

confidence: 99%

“…According to the results available in the literature, in aqueous solution both PEG (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37) and dextran (38)(39)(40)(41) can adsorb on silica surface through hydrogen bonding. Therefore, when silica particles are dispersed in the PEG/dextran system, a competitive adsorption process occurs at the solid/liquid interface between these two polymers.…”

Section: Effect Of Ph On Silica Partition In the Peg/dextran Systemmentioning

confidence: 99%

“…Above the pzc of silica, there is coulombic attraction between cationic surfactants and the negatively charged solid surface. At the same time, PEG can adsorb on the silica surface through hydrogen bonding (27)(28)(29)(30)(31)(32)(33)(34), which transfers the particles into the top phase. Since dextran has only a poor affinity for SiO 2 (38)(39)(40)(41), the polysaccharide adsorption is not so important.…”

Section: Dtabmentioning

confidence: 99%

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Aqueous Biphase Extraction for Processing of Fine Coal

Osseo‐Asare¹

2001

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Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behaviors of silica in the polyethylene glycol (PEG)/dextran (Dex) and dextran/Triton X-100 (TX100) systems have been investigated, and the effects of sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) on solid partition have been studied. In both biphase systems, silica particles stayed in the top PEG-rich phase at low pH. With increase in pH, the particles moved from the top phase to the interface, then to the bottom phase. At very high pH, the solids preferred the top phase again. These trends are attributable to variations in the polymer/solid and nonionic surfactant/solid interactions. Addition of ionic surfactants into these two systems introduces a weakly charged environment, since ionic surfactants concentrate into one phase, either the top phase or the bottom phase. Therefore, coulombic forces also play a key role in the partition of silica particles because electrostatic attractive or repulsive forces are produced between the solid surface and the ionic-surfactant-concentrated phase. For the PEG/dextran system in the presence of SDS, SiO 2 preferred the bottom dextran-rich phase above its pH PZC . However, addition of DTAB moved the oxide particles from the top phase to the interface, and then to the bottom phase, with increase in pH. These different behaviors are attributable to the fact that SDS and DTAB concentrated into the opposite phase of the PEG/dextran system. On the other hand, in the dextran/Triton X-100 system, both ionic surfactants concentrated in the top surfactant-rich phase and formed mixed micelles with TX100. Therefore, addition of the anionic surfactant, SDS, moved the silica particles from top phase to the interface or bottom phase. On the other hand, DTAB, a cationic surfactant, attracted the particles to the top phase in the pH range form 4 to 11, where in the DTAB-free system the solids either stayed at the interface or in the bottom phase.

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Section: Effect Of Ph On Silica Partition In the Peg/dextran Systemmentioning

confidence: 98%

Section: Effect Of Ph On Silica Partition In the Peg/dextran Systemmentioning

confidence: 99%

Section: Effect Of Ph On Silica Partition In the Peg/dextran Systemmentioning

confidence: 99%

Section: Dtabmentioning

confidence: 99%

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Aqueous Biphase Extraction for Processing of Fine Coal

Osseo‐Asare¹

2001

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Inelastic Electron Tunneling Spectroscopy

Hipps

Mazur

2001

Handbook of Vibrational Spectroscopy

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The basic concepts of scanning tunneling microscopy (STM) are reviewed, with emphasis on instrumentation appropriate for spectroscopic applications. Applications of scanning tunneling spectroscopy to semiconductor and metal surfaces are discussed. Focus is then placed on the spectroscopy of single molecules adsorbed on surfaces. Examples of molecular images with sub‐molecular resolution are provided. Both inelastic electron tunneling spectroscopy (IETS) and orbital mediated tunneling spectroscopy (OMTS) are discussed. Molecular electronic spectra (OMTS) are displayed and contrasted with results from techniques requiring large (>10 9 ) numbers of molecules. Correlation between the nanoscale method of OMTS, and the microscale methods of ultraviolet photoelectron spectra (UPS) and electrochemical oxidation and reduction potentials will be made. Mapping of electron transport paths through a molecule and mapping of chemical components on a surface are both addressed.

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