PHC320H1 Lecture Notes - Lecture 24: Zeta Potential, Relative Permittivity, Dielectric
24 Mar 2015
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If no surfactant or electrolytes, for some reason, sometimes we can use steric stabilization. There are physical definition of stability: we want pharmaceutical suspension to be stable, stability here can be defined where particles don"t aggregate irreversibly, we want to flocculate and maintain uniformly distributed throhgout the dispersion. Stoke"s law for rate of sedimentation rate of sedimentation (sedimentation velocity, v) , v= P and p0 are densities of the particle and continuous medium or continuous phase. R=radius of particles and z0=viscosity of continuous phase. If sediment, if particles large enough to sediment then flocculation is more desirable. Flocculated system, since rapid settlement of all this aggregation of particles in bottom of container, then sedimentation will be quick and quickly observe sediment and supernatant, supernanta=part of system with no particles, so pure continuous liquid. Flocculation volume =f with simple meaning volume of sediment/volume of system vu/vo.
