Search

In this study, we used a LUMiSizer® analytical centrifuge to determine the particle dispersions and size distributions of organic/inorganic composite coatings. The centrifuge was capable of recording both the measure space and time-resolved extinction profiles (STEP™-Technology) for up to 12 samples simultaneously, making it a powerful tool for the characterization and quality control of coatings. While the variation of the light extinction curves after centrifugal segregation provided a qualitative description, a rigorous formulation can provide detailed quantitative characterization. The technique used in this study allowed demixing to be accelerated and direct quantification of the dispersibility of the coatings. Because the dispersants and binders stabilized the organic/inorganic composite coatings, the dispersibility strongly depended on their concentration. The dispersibility of the coatings increased upon increasing the dispersant concentration and decreasing the concentration of the binder. Furthermore, the inorganic particles exhibited good dispersibility, without large degrees of aggregation, in the coating dispersions. We also used the LUMiSizer® to determine the particle size distribution and shelf life of coatings; the results were comparable with those obtained using dynamic light scattering, scanning electron microscope and zeta potential analysis. [ABSTRACT FROM AUTHOR]