Photon Correlation Spectroscopy, Transient Electric Birefringence, and Characterization of Particle Size Distributions in Colloidal Suspensions
Download Full Text
Chapter 8 from Particle Size Distribution; edited by Theodore Provder.
By using a combination of static and dynamic laser light scattering (LLS) and transient electric birefringence (TEB) we have been able to determine structural characteristics and size distributions of polydisperse disk-shaped particles (bentonite) in suspensions. In the limit of low concentration and scattering angle we obtained the weight-average molecular weight Mw, the z-average radius of gyration 1/2 and the second virial coefficient A2 from static light scattering measurements; at higher scattering angles we were able to estimate an average particle thickness. Photon correlation function measurements of both the polarized and the depolarized components of scattered light give us the average diffusion coefficients DT (translational) and DR (rotational) which can in turn be converted to average particle dimensions. Detailed analysis of characteristic linewidth distributions yield particle size distributions consistent with direct observations using electron microscopy. The TEB experiment provides us with the average optical polarizability difference Δα°, the ratio of permanent dipolar moment to electric polarizability difference, and the average rotational diffusion coefficient DR (TEB). Profile analysis of the decay curve yields a distribution of particle sizes consistent with the results from LLS.
American Chemical Society
Xu, R., Ford, J.R., & Chu, B. (1987). Photon correlation spectroscopy, transient electric birefringence, and characterization of particle size distributions in colloidal suspensions. In T. Provder (Ed.). Particle Size Distribution. (pp. 115-132). Washington D.C.: American Chemical Society.