Forces of interaction between colloidal particles

There are five possible types of force between colloidal particles  

Consideration of the electrostatic repulsion and van der Waals forces of attraction by the Russians Deryagin and Landau and the Dutch scientists Verwey and Overbeek produced a satisfactory quantitative approach to the stability of hydrophobic suspensions. Their theory is known as the DLVO theory of colloid stability, the briefest outline of which is given here. 

Van der Waals forces between particles of the same kind are always attractive. The 

Chapter 7 Emulsions, suspensions and other disperse systems 

The Hamaker constant. A, depends on the properties of the particles and of the medium in which they are dispersed. When H/a is small, that is when the particles are large relative to the distance of separation, equation (7.2) reduces to 

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On the basis of work done in the years just before World War II, Deijaguin and Landau [26] were able to explain in 1941 many of the complex phenomena involved in aggregative stability on the basis of forces of interaction between colloidal particles, namely the van der Waals-London forces of attraction and the electrostatic forces of repulsion. In the meantime, as a result of theoretical investigations and calculations performed in the years 1940-1944 and without the benefit of much of the literature that appeared during the war years, Verwey and Overbeek [7] formulated a theory of stability of lyophobic colloids and published it as a book in 1948. Because their... 

A similar method for evaluating the adhesion of mutually perpendicular fibers (glass, quartz, or metal) with diameters from 0.2 to 1.2 mm was used by G. I. Fuks [96]. He also described an instrument (Fig. III.14) in which the forces of interaction between colloidal particles could be determined by a method involving plane-parallel disks (disk diameter 5-20 mm). The basic part of this instrument consists of the steel or quartz disks 1 and 2 immersed in the test liquid 3. The distance between the disks is measured in terms of the capacitance of the plane-parallel condenser including the disk 2. The lower limit of sensitivity of this method is 0.022-0.025 /mi in this case, the relative error is 12-18%. 

A similar method for estimating the adhesion of mutually perpendicular filaments (glass, quartz, or metal), 0.2-1.2 mm in diameter, was used by Fuks [88]. Fuks also used an apparatus (Fig. 11.19) in which it was possible to determine the forces of interaction between colloidal particles by the method of plane-parallel discs (disc diameters 5-20 mm). 

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