ABSTRACT
Dispersions in both aqueous and nonaqueous media are used in many products including paints, dyestuffs, pigments, printing inks, papers, adhesives, cosmetics, detergents, ceramics, and pharmaceutical and pesticidal formulations. Use of coagulants to clarify drinking water was practiced in ancient China and Egypt. Mineral and environmental engineers have applied the concepts of colloid science to help them utilize and preserve enormous resources which otherwise was waste material [1]. Nowadays, ceramic products ranging from building bricks to expensive China to rocket parts are made from clay=water sols by
in the areas of cosmetics and detergents has added many products into our daily life [3]. Knowledge of human life, either written on paper or stored on the film or disk, has depended upon the application of colloidal science in paper making and development of new magnetic and electronic materials. High-quality ceramics are also very important as substrates for electronic devices and are used in the preparation of capacitors, ferrites, and piezoelectrics [4]. The initial excitement of the discovery of the high-temperature superconducting oxide phases has been considerably dampened by the inability to process them into mechanically strong and durable products. The main reason for the structural failure of ceramic materials is the presence of flaws in the material, which facilitates initiation and propagation of cracks. These flaws are introduced into the material during the powder-processing stage and hence the future of ceramics, to a great extent, will depend on the control of the state of dispersion of the powder before firing [5]. Agglomerates and inhomogeneities in the dispersion result in poor packing, grain growth porosity, and other defects. Good initial dispersion of ceramic powders in liquids is essential for production of high-quality ceramics. The similarity between some biological systems and colloid dispersions, such as blood and proteins and polyelectrolytes [6], has made colloid science more attractive to the scientific community. The successful applications of colloidal concepts in biological system include encapsulation, controlled drug release, and prevention or promotion of cell adhesion [7].
