Colloids stabilization, polymer adsorption

Stabilization of Colloidal Dispersions by Polymer Adsorption, Tatsuo Sato and Richard Ruch... 

T Sato, R Ruch. Stabilization of Colloidal Dispersions by Polymer Adsorption (Surfactant Science Series, No. 9). New York Marcel Dekker, 1980, pp 65-119. 

Emulsions and Emulsion Technology (in three parts), edited by Kenneth J. Lissant Anionic Surfactants (in two parts), edited by Warner M. Linfieid see Volume 56) Anionic Surfactants Chemical Analysis, edited by John Cross Stabilization of Colloidal Dispersions by Polymer Adsorption, Tatsuo Sato and Richard Ruch... 

Protective Colloids. Another approach in preparing and stabilizing metal colloids is by adsorption of macromolecules on their surfaces. A wide variety of materials have been used including gummy gelatinous liquids,(J 0) albumin,(27) Icelandic moss,(28) latex,(22) polyvinylpyrrolidone, (29) antibodies, ( 30 ) carbowax 20M, ( 31 ) polyvinylpyridine, (31 ) and various polymer-water/oil-water mixtures.( 2) These studies clearly indicate that "steric stabilization of metal colloids is also important (along with electronic stabilization).(33)... 

Other applications. Displacement must also have its impact on colloidal stability. The relation between the adsorption of polymers on colloidal particles and the resultant steric stability... 

Polymer adsorption is important in the flocculation and stabilization of colloidal sols and has been reviewed by Vincent et al. (1) and Tadros (2). Polyvinyl alcohol (PVA) has been used in these studies because of its practical application in textiles, adhesives, and coatings. The adsorption of PVA has been studied on silver iodide by Fleer (3) and Koopal (4), and on polystyrene (PS) latex particles by Garvey (5). The adsorption isotherms reported by these workers extend up to 600 ppm PVA. The adsorption at... 

Polymer Adsorption at the Lower Critical Solution Temperature and Its Effect on Colloid Stability... 

Adsorption behavior and the effect on colloid stability of water soluble polymers with a lower critical solution temperature(LCST) have been studied using polystyrene latices plus hydroxy propyl cellulose(HPC). Saturated adsorption(As) of HPC depended significantly on the adsorption temperature and the As obtained at the LCST was 1.5 times as large as the value at room temperature. The high As value obtained at the LCST remained for a long time at room temperature, and the dense adsorption layer formed on the latex particles showed strong protective action against salt and temperature. Furthermore, the dense adsorption layer of HPC on silica particles was very effective in the encapsulation process with polystyrene via emulsion polymerization in which the HPC-coated silica particles were used as seed. 

Among the various branches in colloid and interface science, polymer adsorption and its effect on the colloid stability is one of the most crucial problems. Polymer molecules are increasingly used as stabilizers in many industrial preparations, where stability is needed at a high dispersed phase volume fraction, at a high electrolyte concentration, as well as under extreme temperature and flow velocity conditions. 

In this study, adsorption behavior of water soluble polymers and their effect on colloid stability have been studied using polystyrene latices plus cellulose derivatives. As the aqueous solution of hydroxy propyl cellulose(HPC) has a lower critical solution temperature(LCST), near 50 °C(6 ), an increased adsorption and strong protection can be expected by treating the latices with HPC at the LCST. 

FURUSAWA FT AL. Polymer Adsorption at LCSTand Colloid Stability 133... 

In the micellar region the trend to decreasing colloid stability is arrested and a partial improvement, in line with the enhanced level of polymer adsorption, is noted until the conditions for gross phase separation are reached. Only the intermediate block copolymer BC 42 shows indications of discontinuities in behavior at the solvent composition for micelle formation. The results presented here do not show the sharp transition from stability to instability found experimentally (4,8,17) by Napper and generally expected on theoretical grounds. However, there are important differences in experimental methodology that must be emphasised. 

Sato, T. Ruch, R., Stabilization of Colloidal Dispersion by Polymer Adsorption, Marcel Dekker, Inc., NY, 1980. 

As will be discussed in Chapter 7, the adsorption of polymers may either increase or decrease colloid stability. 

Polymer brushes were found to minimize adsorption of proteins by the soft or steric repulsion of the flexible yet immobihzed macromolecules [179], although a generally valid explanation of the protein resistant properties of some hydrophihc brushes is not available. A similar explanation can be formulated for the improvement of the colloidal stability of particle suspensions, when polymer brush-type layers are bound to small particles. This and other intriguing features of polymer brushes prompted a remarkable experimental and theoretical research activity in order to understand and exploit the unique properties of polymer brushes. 

Sato, T. and Ruch, R. Stabilization of colloidal dispersions by polymer adsorption, New York Dekker 1980... 

There are very important phenomena originated when a polymer is on one interface or close to one interface. Such phenomena include adsorption, adhesion, monolayer formation, coating and colloidal stabilization. In the majority of circumstances a polymer adsorbed onto colloidal particles will increase the stability of a dispersion [8], The essential feature of polymer or steric stabilization is... 

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