Controlled colloidal aggregation

Near-IR Metal Enhanced Fluorescence And Controlled Colloidal Aggregation... 

A major obstacle in making precise structures with metal colloids has been the control of aggregation and particle size distribution. The use of micelles has allotted some success in this regard with the formation of different metal colloid geometries [30]. It is known that the nanoparticles must be stabilized by organic molecules attached to their surface [31] and in general must be embedded in a solid matrix [32], This is done to prevent agglomeration and precipitation as... 

The major drawback of these classical views is that they fail to take into account the electrical nature of the stable constituents in blood (which are colloidal) and that thrombus formation depends upon factors known to control the aggregation of colloids, namely the electric charge, and its sign and magnitude on the colloids in comparison with that on the arterial walls. 

Interfacial chemistry and system hydrodynamics control the aggregation, deposition, and separation of particles and particle-reactive substances in natural aquatic environments and in many technological systems. Hydrodynamics (particle transport) are particularly sensitive to particle size and size distribution colloidal stability is usually determined by the presence of macromolecular natural organic substances. Recent theoretical and experimental studies of the effects of these two classes of variables on solid-liquid separation in aquatic systems are presented and discussed. 

Fractal structures have been examined, in particular, in diffusion-controlled aggregation process (polymerization) [7-9], in colloids (aggregates of particles) [10-13], and in percolation clusters [1-3],... 

In systems with liquid dispersion medium, i.e. in foams, emulsions, sols and suspensions, there is a broad variety of means to control colloid stability. In these systems the nature of colloid stability depends to a great extent on the aggregate state of dispersed phase. Similar to aerosols, foams are lyophobic, but in contrast to them can be effectively stabilized by surfactants. Properties of emulsions, and, to some extent, those of sols may be quite close to the properties of thermodynamically stable lyophilic colloidal systems. In such systems a high degree of stability may be achieved with the help of surfactants. 

Separation of charge and size effects for organics and ion separation and the effect of speciation Effect of pretreatment on membrane processes for rejection enhancemenr and fouling control. Colloidal fouling experiments with model colloidal systems and known aggregation behaviour... 

By carbonization of a thin layer of phenolic resin on the suitable templates, Gierszal et al. [108] reported the synthesis of one kind of uniform carbon film with large pore volumes (6 cm g for 24 mn silica colloids), uniform pore sizes, and controlled thickness. This synthetic route involves the formation of a uniform polymeric film on the silica pore walls of silica colloidal crystals or colloidal aggregates and its carbonization and tanplate removal. After proper pre-treatment of the sihca... 

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