Mixture colloidal mixtures

Colloidal Mixtures—Colloids are an important intermediate state between a true solution and a heterogeneous mixture. Colloidal mixtures are responsible for some unusual phenomena (Fig. 14.25) and are encountered in a broad range of contexts, from fluids in living organisms to pollutants in large air masses (Table 14-5). 

In the previous section, non-equilibrium behaviour was discussed, which is observed for particles with a deep minimum in the particle interactions at contact. In this final section, some examples of equilibrium phase behaviour in concentrated colloidal suspensions will be presented. Here we are concerned with purely repulsive particles (hard or soft spheres), or with particles with attractions of moderate strength and range (colloid-polymer and colloid-colloid mixtures). Although we shall focus mainly on equilibrium aspects, a few comments will be made about the associated kinetics as well [69, 70]. 

Single-base propellants are mixed in a similar fashion by adding the ingredients to the nitrocellulose in the mixer together with the required amounts of ether and alcohol. The mixing time is about one-half hour, and the temperature is kept below 25°C. The pardy colloidal mixture looks like moist cmde sugar. A maceration step may be included to increase homogeneity. 

Short-time Brownian motion was simulated and compared with experiments [108]. The structural evolution and dynamics [109] and the translational and bond-orientational order [110] were simulated with Brownian dynamics (BD) for dense binary colloidal mixtures. The short-time dynamics was investigated through the velocity autocorrelation function [111] and an algebraic decay of velocity fluctuation in a confined liquid was found [112]. Dissipative particle dynamics [113] is an attempt to bridge the gap between atomistic and mesoscopic simulation. Colloidal adsorption was simulated with BD [114]. The hydrodynamic forces, usually friction forces, are found to be able to enhance the self-diffusion of colloidal particles [115]. A novel MC approach to the dynamics of fluids was proposed in Ref. 116. Spinodal decomposition [117] in binary fluids was simulated. BD simulations for hard spherocylinders in the isotropic [118] and in the nematic phase [119] were done. A two-site Yukawa system [120] was studied with... 

A solid propellant is a mechanical (heterogeneous) or a chemical (homogeneous, or colloidal) mixture of solid-state fuel and oxidizer-rich chemicals. Specially-formed charges of solid propellant (grains) arc placed in the combustion chamber of the solid rocket motor (SRM) at a production facility. Once assembled, the engine does not require additional maintenance, making it simple, reliable and easy to use. 

Chen YH, Yeh CS (2001) A new approach for the formation of alloy nanoparticles laser synthesis of gold-silver alloy from gold-silver colloidal mixtures. Chem Commun 371-372... 

Animal glue is a complex colloidal mixture of proteins. The related gelatins are also complex heterogeneous mixtures of proteins. They are strongly hydrophilic and rich in the amino acids glycine, proline, lysine, hydroxyproline and hydroxylysine. Casein is a phosphoprotein obtained from the milk of mammals. 

F. Leal-Calderon, J. Bibette, and J. Biais Experimental Phase Diagrams of Polymer and Colloid Mixtures. Europhys. Lett. 23, 653 (1993). 

It, of course, was not possible for Fischer to make a naturally occurring protein because at that time no structure of a protein was known. In fact, many believed that proteins were not even discrete single large molecules, but were actually colloidal mixtures of smaller compounds. It was, however, possible for Fischer to apply his new methods to the synthesis of large peptides that he felt would simulate the properties of natural proteins. 

Kaplan PD, Rouke JL, Yodh AG, Pine DJ (1994) Entropically driven surface phase separation in binary colloidal mixture. Phys Rev Lett 72 582-585... 

Cumper and Alexander ( ) and Cumper (T) explained that during foam formation, a monolayer of surface denatured protein surrounded by liquid is rapidly adsorbed at the interface of the colloidal mixture, trapping air and forming bubbles (Table I,... 

Other dimensionless groups that compare the thickness of the adsorbed polymer layer to the radius of the particle or the radius of gyration of the polymer to the particle radius in polymer/colloid mixtures can also be easily defined. We are mostly concerned with the volume fraction and the Peclet number Pe in our discussions in this chapter. However, the other dimensionless groups may appear in the equations for intrinsic viscosity of dispersions when the dominant effects are electroviscous or sterically induced. 

Theoretical studies of the role of polymer additives lag behind their analogs in electrostatic stability since polymer molecules have considerably more configurational freedom and since the interaction of the polymer molecules with the solvent is an inseparable part of phenomena in polymer-colloid mixtures. We begin with some of the general issues and a thermodynamic analysis of the role of polymer on stability in Section 13.5. 

Why does polymer solution thermodynamics play an important role in polymer-colloid mixtures ... 

Electrophoretic Analysis of colloidal mixtures was developed by Tiselius (Ref 1). 

Refs 1) A. Tiselius, TransFaradSoc 33, 524(1937) (A new apparatus for electro-pho retie analysis of colloidal mixtures)... 

Tiselius, A., 1937. A new apparatus for electrophoretic analysis of colloidal mixtures. Trans. Faraday Soc., 33 52 -531. 

Dekany, I., Berger, F., Imrik, K. and Lagaly, G. (1997). Hydrophobic layered double hydroxides (LDHs) Selective adsorbents for liquid mixtures. Colloid Polym. Sci. 275, 681. 

Tablet glidant Agent used in tablet and capsule formulations to improve flow properties of powder mixture Colloidal silica, corn starch, talc...

Note During the dehydration procedure described in Vol 3, p C399-L, it is required to determine ethanol and water in the cylindrical block removed from the press. In these detns a piece of block (cake) is dried in an oven at 100° to obtain "total volatile content , the water is detd by Karl Fischer Method and then ale is obtd by difference. Finally ether is added to make a colloiding mixture contg 2 parts of ether to 1 part alcohol by wt. The above tests are described in the items which follow... 

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