Characterization of colloidal nanoparticles in mixtures with polydisperse and multimodal size distributions using a particle tracking analysis and electrospray-scanning mobility particle sizer

Characterization of polydisperse liquid-borne particles was investigated using a particle tracking analysis (PTA) and electrospray-scanning mobility particle sizer (ES-SMPS). The results showed PTA measurements based on light scattering accurately predicted mode sizes of monodisperse colloidal particles, but the geometric standard deviation of 40 nm polystyrene latex (PSL) particles was underestimated because of a screening effect that makes the smaller particles less visible. ES-SMPS could precisely predict the size distributions with sizes and standard deviations of monodisperse particles when compared to scanning electron microscopy data. From the results for the mixture of 40 nm Au and PSL and mixtures of 40 nm Au and 100, 150 and 240 nm PSL, it was shown that ES-SMPS is a very promising method to characterize colloidal particles with a wide or multimodal size distributions. Therefore, the results of this study provide detailed insights into various applications that require accurate characterizations of polydisperse colloidal particles.