EFFECT OF ELECTRODE GEOMETRY AND CHARGE ON THE PRODUCTION OF POLYMER MICROBEADS BY ELECTROSTATICS

Experimental parameters which are critical for producing small diameter (i.e. 100-300 mum) polymer microbeads, using electrostatic droplet generation, were investigated with three types of electrodes; a parallel plate, a positively charged needle and a grounded needle with alginate as the polymer. Electrode spacing was a critical factor controlling microbead size, but only for the parallel plate set-up. While the applied potential affected droplet size in all three set-ups, the smallest droplet size was produced with the positively charged needle. In some experiments needle oscillation was observed resulting in even smaller microbeads (i.e. < 100 mum). Calculated microbead diameters agreed well with experimental values.