To determine the diameter of spherical monodisperse PSL (polystyrene latex) particles, the following accurate and simple methods have been examined ; 1) simplified Millikan's method, 2) gravitational sedimentation method, and 3) electrical mobility method. Among these methods, it was found that the first one was very useful for particles having diameters around 1 μm and the third one which had been well calibrated by the Millikan's method was useful for smaller particles. Although the standard deviation of particle size distribution could not be determined in this study, the methods to determine mode and arithmetic mean diameters will be useful for calibration of size analyzers including electron microscopies.
A polynomial approximation model (PAM) of correlogram was presented to improve a data reduction of photon correlation spectroscopy (PCS), and was applied to a particle sizing of aerosols. Diameters of submicron aerosol and alcosol particles were obtained for several sizes of polystyrene latex (PSL) particles by the PCS with two correlation models ; the one is the PAM and the other is a usual correlation model (UCM) on self-diffusion of particle. The particle size determined by UCM was consistent with nominal diameter for alcosols, however, the reduced size of aerosols showed twice or more in diameter by UCM. The diameter determined using PAM was in good agreement with that obtained by electron-microscopy even in aerosols. The method was also applied to an in-situ measurement of particle growth by thin film coating of Methy1-2-Cyano-Acrylate vapor on 497 nm PSL aerosol particles, and a growth rate of 3 × 10-11 m/s was obtained at 40°C.