Abstract
An ultrasound (US) irradiation technique was applied to obtain the rod-like L-aspartic acid crystal in cooling crystallization process. In experiments, the 20 kHz horn-type transducer was installed vertically into the aqueous solution. Experimental results confirmed that arithmetic mean and ratio of breadth and length of a formed crystal can be reasonably controlled by US intensity and irradiation time. The high yield of rod-like crystals was obtained under the conditions of 46 W/cm2 US intensity and 1 min irradiation time. SEM and XRD analysis demonstrated that all crystals formed in this study were plate like α-form, and that rod-like crystals formed by US irradiation were revealed to be the polysynthetic twin composed of small size plate-like crystals.
