Influence of Piezoelectric Properties on the Ultrasonic Dispersion of TiO2 Nanoparticles in Aqueous Suspension

In this study, the soft-type and hard-type lead zirconate titanate (PZT) ceramics were compared in order to create an optimal system for ultrasonic dispersion of nanoparticles, and sound pressure energy for each PZT ceramic was analyzed and closely examined with ultrasonic energy. TiO2 was water-dispersed using the soft-type and hard-type PZT transducer, possessing different characteristics, and its suspension particle size and distribution, polydispersity index (PDI), zeta potential, and dispersion were evaluated for 180 days. Furthermore, it was confirmed that the particles dispersed using the hard-type PZT transducer were smaller than the particles dispersed using the soft-type PZT by 15 nm or more. Because the hard-type PZT transducer had a lower PDI, uniform particle size distribution was also confirmed. In addition, by measuring the zeta potential over time, it was found that the hard-type PZT transducer has higher dispersion safety. In addition, it was confirmed that the ultrasonically dispersed TiO2 suspension using a hard-type PZT transducer maintained constant particle size distribution for 180 days, whereas the suspension from the soft-type PZT aggregated 30 days later. Therefore, the hard-type PZT is more suitable for ultrasonic dispersion of nanoparticles.