ABSTRACT
Colloidal solutions are preferred for pharmaceutical applications, where maximizing the surface area of the dispersed phase is important. On the basis of the type and extent of molecular interactions of the dispersed phase with the dispersion medium, colloidal systems can be classified into three groups: lyophilic, lyophobic, and association colloids. This chapter discusses how the electrical properties of colloids can be used for improving their physical stability. It describes the electrical, kinetic, and colligative properties of colloids. In colloidal dispersions, frequent interparticle collisions due to Brownian movement can destabilize the system. Thus, increase in temperature often compromises the physical stability of these systems. Properties of colloidal systems that arise from the motion of particles with respect to the dispersion medium are known as kinetic properties. These include Brownian motion, diffusion, sedimentation, and osmosis. The colloid-rich layer is known as a coacervate, and the phenomenon by which macromolecular solutions separate into two liquid layers is referred to coacervation.
