Interfacial deposition

Smith, D.N., Edwards, H.G.M., Hugues, M.A., Courtney, B. 1997. Odorless kerosene degradation and the formation of interfacial deposits during the alkaline solvent wash in the PUREX process. Sep. Sci. Technol. 32(17) 2821-2849. 

Santos-Magalhaes et al. [27] reported on PLGA nanocapsules/nanoemulsions for benzathine pencillin G. Nanoemulsions were produced by spontaneous emulsification and nanocapsules by interfacial deposition of the pre-formed polymer. They have observed similar release kinetics from both formulations [27]. 

Poly(s-caprolactone) Poly(e-caprolactone) is a semicrystalline polymer synthesized by anionic, cationic, free-radical, or ring-opening polymerization [94]. It is available in a range of molecular weights and degrades by bulk hydrolysis autocatalyzed by the carboxylic acid end groups. The presence of enzymes such as protease, amylase, and pancreatic lipase accelerates polymer degradation [95], The various methods of preparation of poly(e-caprolactone) nanoparticles include emulsion polymerization, interfacial deposition, emulsion-solvent evaporation, desolvation, and dialysis. These methods and various applications are extensively reviewed [94],... 

Poster S, 1998, Routes to Interfacial Deposition of Platinum Microparticles for Solid Polymer Fuel Cells, PhD Thesis, University of Loughborough. 

Aggregation and fragmentation of colloidal particles has been investigated further employing natural polyelectrolytes like humic substances. Adsorption of humic acids on aluminum oxide was determined to resemble interfacial deposition on the basis of methods previously employed for the aluminum oxide/polyacrylic acid system [88]. Complexation by soluble aluminum ions produces pH drops that are very similar to that determined for polyacrylic acid, and essentially humic acids were determined to exert effects on the stability of colloidal aluminum oxide particles at pH 5 that are very similar to polyacrylic acid. 

Investigation of the mode of interfacial deposition and the local structure of transition metal ionic species formed upon impregnation at the catalytic support/electrolytic solution interface... 

An alternative method used for preparing supported catalysts is the Equilibrium Deposition Filtration (EDF) technique, otherwise called equilibrium adsorption. Following this technique the support is immersed in a large volume of a dilute aqueous solution of the TMIS, ideally at fixed pH and ionic strength. Equilibration of the suspension follows for several hours under stirring. During equilibration the TMIS are deposited at the interface developed between the support surface and the aqueous solution. We call this mode of deposition interfacial deposition. In the filtration step the interfacially deposited TMIS are practically separated from the non-deposited ones. 

It has been reported several times that the type of deposition strongly affects the physicochemical characteristics and thus the catalytic behavior of the final catalysts [1,2]. In most of the cases, interfacial deposition results to catalysts with very small supported particles. This is because their size is controlled by the physicochemical characteristics and the size of the interface. Therefore, interfacial deposition results to supported catalysts with very high dispersion of the supported phase [2]. This is frequently reflected to the relatively high activity of the final catalysts [2]. 

Relatively recent results indicate that the mode of the interfacial deposition and the local sfructure of the iimer sphere complexes, eventually formed, may influence remarkably the surface characteristics and thus the catalytic behavior of the final supported catalysts [2,5-7]. In view of the above, it is clear that the determination of the mode of interfacial deposition and the local stmcture, which predominate under given impregnation conditions, may be proved an extremely useftil tool for catalyst preparation, because it allows their control by regulating the impregnation parameters. 

The interfacial deposition of these complexes was studied at 25°C, pH range 6.0-7.5, metal concentration range 10 -2xl0 M and I=0.1N. Under our... 

Figure 3. Local Structures of the surface inner sphere complexes formed upon interfacial deposition of the Co(II) aqua complexes on titania surface.

The interfacial deposition of W04 and HxWyOw at pHs 9-4 and 6-4, respectively, is also detected in the LR spectra recorded after equilibration of the suspensions and filtration (Fig. 5). At high pH values the characteristic peak... 

Figure 6. Local structures of the tungsten-oxo species interfacially deposited on titania at the entire pH range.

The interfacial deposition of the Co(H20)6 and Ni(H20)6 ions results to the formation of inner sphere surface complexes. Mononuclear inner sphere complexes are formed at relatively high pH values whereas at relatively low pH values polymeric oxo-species are retained, in addition to the monomers, mainly through electrostatic forces. The Cr oxo-species are deposited mainly through electrostatic forces. 

The deposition of Cr on two fluorinated poly(aryl ether) (rPAE) polymers has been investigated with x-ray photoelectron spectroscopy. Fluorine moieties were observed to be highly reactive towards the deposited Cr. Differences in polymeric fluorine chemistry (aliphatic vs. aromatic) did not affect the reaction pathway or the final reaction products. Interfacial deposition products form in a step-wise fashion dependent upon sietal coverage. A model ie proposed whereby the formation of reaction products is initiated by electron transfer from the metal to tha polymer followed by the formation of Cr-fluorldes and finally Cr-carbldes prior to the formation of a continuous unreacted metal overlayer. 

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