Colloid surface rheology

J. Lakatos-Szabd and I. Lakatos. Effect of sodium hydroxide on interfacial rheological properties of oil-water systems. In Colloids Surfaces, Sect A, volume 149, pages 507-513. 9th Surface Colloid Sci Int Conf (Sofia, Bulgaria, 7/6-7/12), 1997. 

D Miller, EM Wiener, A Turowski, C Thunig, H Hoffmann. O/W emulsions for cosmetic products stabilized by alkyl phosphates rheology and storage tests. Colloids Surfaces A Physicochem Eng Aspects 152(1-2) 155-160, 1999. 

Dickinson, E. (1999b). Adsorbed protein layers at fluid interfaces interactions, structure and surface rheology. Colloids and Surfaces B Biointerfaces, 15, 161-176. 

In considering the impact of thermodynamically favourable interactions between biopolymers on the formation and stabilization of food colloids, a number of regular trends can be identified. One of the most important aspects is the effect of complexation on interfacial properties, including rates of adsorption and surface rheological behaviour. 

The answer is yes. In fact, in many colloidal systems containing large liquid-fluid Interfaces, such as foams and emulsions, there is abundemt evidence for the action of surface rheology in addition to the omnipresent rheology of the adjoining bulk phases. Let us give three illustrations. 

The lUPAC recommendation Manual of Symbols and Terminology for Physicochemical Quantities and Units Appendix II Definitions Terminology and Symbols in Colloid and Surface Chemistry, Part 1.13 Selected Definitions, Terminology and Symbols for Rheological Properties, Pure Appl. Chem. 51 (1979) 1213 also contains recommendations for surface rheology. Only part of them are heeded in this chapter. 

Loglio G, Pandolfini P, Tesei U, and Noskov B (1998b) Measurements of interfacial properties with the axisymmetric bubble-shape analysis technique effects of vibrations. Colloids Surfaces A 143 301-310 Loglio G, Pandolfini P, Miller R, Makievski AV, Ravera F, Ferrari M and Liggieri L (2001) "Drop and Bubble Shape Analysis as Tool for Dilational Rheology Studies of Interfacial Layers", in "Novel Methods to Study Interfacial Layers", Studies in Interface Science, Vol. 11, D. Mobius and R. Miller (Eds.), Elsevier, Amsterdam, pp 439-485... 

Bames, H,A. Rheology of emulsions—a review. Colloid Surfaces A Physicochem, Eng. Aspects, 91 89-95, 1994. 

Miano. F. Rabaioli, M.R. Rheological scaling of montmorillontle suspensions the effect of electrolytes and polyelectroiytes. Colloid Surfaces A Physicocheni. Eng. Aspects, 84 229-237. 1994. 

Mannheimer, R.J. and Schecter, R.S., An improved apparatus and analysis for surface rheological measurements, J. Colloid Interface Sci., 32, 195, 1970. 

The chapters in this book deal with specific research situations, firom both the experimental and theoretical points of view. To conceptually unify what appears to be a diverse collection of work on disparate systems, an overview chapter by William B. Russel serves as an introduction. This chapter reviews various phenomena such as flocculation, stabliliza-tion, phase separation, and rheology of colloidal particles in polymer solutions, which are all recognized as macroscopic manifestations of the short-range forces between polymer segments and colloid surfaces. 

The second factor to influence fine particle and colloidal suspension rheology is the interaction force between the particles. (The first factor being the volume fraction of particles.) The sense (attractive or repulsive), range and magnitude of the surface forces all influence the suspension rheological behaviour. 

Dickinson, E. (2001) Milk protein interfacial layers and the relationship to emulsion stability and rheology. Colloid. Surface. B, 20,197. 

Anton, M., Le Denmat, M., Beaumal, V. and Pilet, P. (2001) Filler effects of oil droplets on the rheology of heat-set emulsion gels prepared with egg yolk and egg yolk fractions. Colloid. Surface. B, 21, 137. 

Adams-Viola, M., Botsaris, G.D., Filymer, W.G., Jr., Glazman, Yu.M. and King, K.D. (1982) The effect of coal particle aggregation on the sedimentation and rheology of coal-oil mixtures. Colloids Surfaces, 4,255-69. 

Llamas, S., Mendoza, A.J., Guzman, E., Ortega, F., Rubio, R.G. Salt effects on the air/ solution interfacial properties of PEO-containing copolymers equilibrium, adsorption kinetics and surface rheological behavior. J. Colloid Interface Sci. 400, 49-58 (2013)... 

A. Tonck, J. M. Georges, J. L. Loubet. Measurements of intermolecular forces and the rheology of dodecane between alumina surfaces. J Colloid Interface Sci 72(5 150-163, 1988. 

Molecularly motivated empiricisms, such as the solubility parameter concept, have been valuable in dealing with mixtures of weakly interacting small molecules where surface forces are small. However, they are completely inadequate for mixtures that involve macromolecules, associating entities like surfactants, and rod-like or plate-like species that can form ordered phases. New theories and models are needed to describe and understand these systems. This is an active research area where advances could lead to better understanding of the dynamics of polymers and colloids in solution, the rheological and mechanical properties of these solutions, and, more generally, the fluid mechaiucs of non-Newtonian liquids. 

To address these challenges, chemical engineers will need state-of-the-art analytical instruments, particularly those that can provide information about microstmctures for sizes down to atomic dimensions, surface properties in the presence of bulk fluids, and dynamic processes with time constants of less than a nanosecond. It will also be essential that chemical engineers become familiar with modem theoretical concepts of surface physics and chemistry, colloid physical chemistry, and rheology, particrrlarly as it apphes to free surface flow and flow near solid bormdaries. The application of theoretical concepts to rmderstanding the factors controlling surface properties and the evaluation of complex process models will require access to supercomputers. 

The surface force apparatus (SFA) is a device that detects the variations of normal and tangential forces resulting from the molecule interactions, as a function of normal distance between two curved surfaces in relative motion. SFA has been successfully used over the past years for investigating various surface phenomena, such as adhesion, rheology of confined liquid and polymers, colloid stability, and boundary friction. The first SFA was invented in 1969 by Tabor and Winterton [23] and was further developed in 1972 by Israela-chivili and Tabor [24]. The device was employed for direct measurement of the van der Waals forces in the air or vacuum between molecularly smooth mica surfaces in the distance range of 1.5-130 nm. The results confirmed the prediction of the Lifshitz theory on van der Waals interactions down to the separations as small as 1.5 nm. 

Intermolecular Forces and the Rheology of Dodecane Between Alumina Surfaces, J. Colloid Interface Sci., Vol. 126, No. 1, 1988, pp. 150-163. 

I. C. Callaghan, C. M. Gould, R. J. Hamilton, and E. L. Neustadter. The relationship between the dilatational rheology and crude oil foam stability 1. Preliminary studies. Colloids and Surfaces, 8(1) 17-28, November 1983. 

In the processing of foods and additives, rheological and mechanical properties, which determine end use properties are of primary significance. These properties are also related to others such as the impact of taste. Taste is the perception on the taste buds on the surface of the tongue, and colloidal properties will thus have an important role. Gels are also known to be used in many food products. The stability of food products is determined by colloidal stability in many systems (Dickinson, 1992 Friberg, 1976). 

However, the methods presented in this article do not give the big picture of techniques available to colloid scientists. A host of methods had to be left out for brevity s sake, including fields as imporfanf as rheology [10], which concerns ifself wifh fhe flow characferisfics of liquids, measurements of the electric conductivity, and surface tension, to name but a few. 

Dickinson, E., Golding, M. (1998). Influence of calcium ions on creaming and rheology of emulsions containing sodium caseinate. Colloids and Surfaces A Physicochemical and Engineering Aspects, 144, 167-177. 

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