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Brief note on Particle Size Measurement and Zeta Potential

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					Brief note on Particle Size Measurement and Zeta Potential


Particle Size Measurement

Particle size is a geometric characteristic that is usually assigned to material objects with
sizes on scale from nanometers to millimeters. There are multiple definitions of the
particle size depending on the method of its measurement. For instance, sedimentation
yields equivalent hydrodynamic particle size. Microscopy provides information on the
area projection particle size. In order to reflect innate basis for a particular particle size
measurement, three different bases are used: numerical, area and weight. Particle size
measurement is an extremely important method for research and development and for
quality control in many industries. This includes pharmaceuticals, cement, ceramics,
paints, emulsions, etc.




Zeta potential is a parameter characterizing electrochemical equilibrium on interfaces.
It depends on the properties of the liquid as well as on properties of the surface. It plays
an important role in theory of aggregative stability – DLVO theory. Electrostatic
repulsion between particles depends on the value of zeta potential. The higher the zeta
potential, the stronger the repulsion, and thus the more stable the system becomes. For
instance, high zeta potential of the fat droplets in milk prevents them against
coalescence. Reduction of it due to addition of acid would lead to cheese formation
from coalescence droplets

				
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Description: Particle size is a geometric characteristic that is usually assigned to material objects with sizes on scale from nanometers to millimeters.