Potential of High-Powered Bath-Type Ultrasonicator for Manufacturing of Emulsifier-Free Emulsions

摘要

We report here on the manufacturing methods for emulsifier-free (EF-) oil-in-water (O/W) emulsions, in which oil and water were mechanically mixed in the absence of any emulsifiers such as surfactants. A commercially available bath-type ultrasonic cleaner (Bath-US* 42 kHz, 26 W) did not disperse dodecane (DD) completely in water even by the treatment for15 min， and the average diameter of DD droplets in the EF-dodecane-in-water (DD/W) emulsions prepared was several micrometers. Using a commercially available horn-type ultrasonic homogenizer (Horn-US; 19.5 kHz, 600 W)， the EF-DD/W emulsions were prepared by treatment for～1min， and the average diameter of DD droplets in EF-DDAV emulsions prepared was～1(im. Preparation of EF-DD/W emulsions using a high-powered bath-type ultrasonicator (HPBath-US; 28 kHz, 300 W) that we developed required the treatment period for ~1min. The DD droplets in EF-DD/W emulsions prepared with HPBath-US became several hundred nanometers in diameter by treatment for～10 min. The preparation of EF-DD/W emulsions with a commercially available rotor-stator homogenizer (RS-HG; 15,000 rpm, 800 W) required the treatment period for～1min, and DD droplets in DD/W emulsions prepared were several micrometers in diameter. Colloidal stability of EF-DD/W emulsions prepared with Horn-US and HPBath-US was higher than that of EF-DD/W emulsions prepared with Bath-US and RS-HG. These studies indicate that HPBath-US has advantages for the manufacturing of EF-O/W emulsions. Furthermore, the continuous manufacturing of EF-DD/W emulsions was achieved by attaching the flow chamber with HPBath-US.