Preparation of microspheres by an emulsification-complexation method.

Microspheres were prepared by complexation of a cationic polymer, polyquaternium-24, and an anionic surfactant, sodium lauryl sulfate (SLS). The cationic polymer solution was emulsified in dimethylsiloxane to give water in silicone emulsion (W/Si), and it was used as a template for the formation of microspheres. The emulsion was dispersed into the SLS solution. In this process, two kinds of droplets, silicone dropletes and microspheres composed of the cationic polymer and SLS, were formed, evidenced by X-ray energy dispersive spectra. The mean diameter of the microspheres was reduced from 105.7 to 64.8 mum as the stirring rate for W/Si preparation increased from 300 to 1000 rpm. It is believed that water droplets in W/Si emulsion, when exposed to SLS solution, could be solidified by the complexation of the cationic polymer and the anionic surfactant.