Characterization of the Volume-based or Number-based Size Distribution for Silica Nanoparticles Using a Unique Combination of Online Dynamic Light Scattering Having a Uni-tau Multi-bit Correlator and High-resolution Centrifugal Field-Flow Fractionation Separator

Abstract

This paper presents a study of the size distributions of colloidal nanoparticles using an online dynamic light scattering (DLS) unit with a uni-tau multi-bit correlator (UMC) combined with a centrifugal field-flow fractionation (CF3) separator. Conventionally, the FFF-UV-MALS system utilizing field-flow fractionation (FFF) combined with a UV detector and multi-angle light scattering instrument (MALS) could be used to obtain the particle size distribution of colloidal nanoparticles. Lately, DLS as a technique to measure the size distributions of colloid materials has become prevalent. However, the DLS instrument will practically measure only the large particles in a multi-modal particle mixture. Therefore, the CF3-DLS w/UMC system that was developed consisted of a CF3 unit connected to an online DLS instrument with UMC. The system could measure the volume- or number-based size distribution with highly quantitative and accurate histograms for multi-modal samples. The size distributions were validated with size distributions obtained by images of an atomic force microscope (AFM). Two types of colloidal silica nanoparticles with different distribution widths were used in this study.