Dynamic Light Scattering is a measurement technique used to determine the size distribution profile of small particles in suspension or polymers in solution. A laser is shot through a polarizer and into a sample; the scattered light is collected by a photomultiplier. The Brownian motion of the particles causes fluctuations in the scattered light. Analyzing the autocorrelation of the scattered light intensity, one obtains the diffusion coefficient of the particles. Then, the hydrodynamic diameter of the particles is then given by Stokes-Einstein equation.
Photo shows our Malvern Nano-ZS analyzer
(Example)The size distribution of CaCO3 nanoparticles in water solution.
Zeta Potential Analyzer
Zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle. The electrophoretic mobility of particles is obtained by driving the particles with an electric field across the dispersion whiles measuring the particle velocity with Laser Doppler Velocimetry. The zeta potential is obtained through Henry’s Equation. Particles with high zeta potential are typically stable against aggregation. Zeta potential is sensitive to solution pH value.