SIZE DISTRIBUTION OF CORE-SHELL LATEX PARTICLES BY STATIC LIGHT SCATTERING. THEORETICAL SIMULATIONS

LUIS A. CLEMENTI; LUIS M. GUGLIOTTA; JORGE R. VEGA

Los Cocos

Simposio; V Simposio Argentino-Chileno de Polímeros; 2009

Universidad Nacional de Cordoba

Static light scattering (SLS) is often used for measuring the particle size distribution (PSD) of dilute coloidal dispersions. For optically-homogeneous spherical particles, the scattering phenomenon is modeled on the basis of Mie theory. For non-homogeneous spherical particles with concentric core-shell morphologies, the scattering phenomenon can be modeled by the Aden-Kerker theory. In this work, two different cases for estimating the PSD, Core Size Distribution (CSD), and Shell Thickness Distribution (STD) of polymeric core-shell colloidal systems are analyzed. Case I assumes that the core population is available, and therefore an estimate of the CSD, can initially be obtained through Mie theory. Then, the PSD, is obtained by solving an optimization algorithm using Aden-Kerker theory. In contrast, in Case II, the CSD is unavailable, and simultaneous estimates of CSD and PSD are obtained in a single step, by directly solving an optimization algorithm using Aden-Kerker theory. Both cases are evaluated with simulated examples. Simulation results indicate that the CSD and the PSD of a core-shell particule population can adequately be estimated from SLS measurements, on the basis of the Aden-Kerker theory. When the core population is independently measured, then the CSD is more reasonably estimated. However, the PSD is accurately estimated even when the core population is unavailable.