Aging of titania hydrosols prepared via ultrasonic processing

Resumo

We have studied the effect of aging conditions on the properties of titania hydrosols produced via ultrasonic processing and containing aggregates of 5-nm-diameter amorphous particles. The results demonstrate that, at room-temperature, 0.44 M to 0.11 M hydrosols are stable for 3 to 22 days. During aging for 40 to 45 days, the properties of 0.01 M to 0.0025 M hydrosols remain unchanged. Aging for a longer time causes the amorphous particles to crystallize in the anatase structure. Raising the temperature to 75°C reduces the induction time to 3–4 h.