Formation of microgel beads by electric dispersion of polymer solutions

Microcapsules are produced by a dropwise addition of one solution into a so lidifying bath. By applying an electrostatic potential between the droplet formation device and the collecting solution, it is possible to obtain smal ler droplets which nle desirable for many applications. Droplet formation m ay, be divided into two phases Under a certain critical value of the electr ic potential U-c, liquid exits the nozzle as droplets. The surface tension decreases with increasing electric potential resulting in a reduction of dr oplet diameter to approximately 200 mu m. At higher electric potential, liq uid exits the nozzle as a jet which subsequently breaks into droplets, whic h are smaller than 200 mu m. In this case, droplet size is mainly determine d by the jet instability (theory of Rayleigh).