Size Information Obtained by Using Static Light Scattering Technique

Detailed investigation of static light scattering $(SLS) $ has been attempted in this work using dilute water dispersions of homogenous spherical particles, poly($N$-isopropylacrylamide) microgels and simulated data. When Rayleigh-Gan-Debye approximation is valid, for large particles, the simple size information, the static radius $R_{s}$ and distribution $G(R_{s}) $, can be accurately obtained from SLS. For small particles, the root mean-square radius of gyration $< R_{g}^{2}>_{Zimm}^{1/2}$ and the molar mass of particles measured using the Zimm plot are discussed. The results show that the molar mass measured using the Zimm plot over the average molar mass of particles is a function of the size distribution. With the assistance of simulated data, the effects of the reflected light and noises have been investigated in detail. Measuring the static radius from the SLS data provides one method to avoid the stringent requirements for the sample quantity and the instrument capability at small scattering angles.