Effect of surfactant micelle size on the dispersibility of aqueous carbon black particle suspensions prepared by ultrasonication

The effective preparation of particle suspensions is crucial. Herein, we focused on the preparation of carbon black particle aqueous suspensions through ultrasonication to investigate the dispersing mechanisms. Various industrial surfactants were used for the preparation, which resulted in two types of dispersion systems. The first type caused the sizes of the particles in the aqueous solutions to decrease when short ultrasonic irradiation times were employed; however, re-agglomeration occurred after longer times were implemented. The second type employed a long ultrasonication dispersing time and was able to achieve and maintain the smallest-sized particles observed without any re-agglomeration occurring. DLS determined the size of the particles, while PFG-NMR assessed the sizes of the surfactant micelles. Upon comparing these two sizes, we found an obvious relationship between the two regarding their changes during the ultrasonication dispersing process. To better understand these phenomena, the DLVO theory was considered and zeta potential measurements were conducted