Production of nano-silica particles in liquid-liquid system by pulsed voltage application

Electrostatic atomization in liquid-in-liquid media has been performed to produce fine droplets with narrow size distribution. The droplet diameter was controlled from mm to mum with applying dc voltage. When ac superimposed on dc voltage was applied, uniformly-sized droplets were produced. The high frequency pulsed voltage was effective to disperse liquid into nm-sized droplets. Water glass aqueous solution was dispersed in alcohol solution, and then they were solidified into solid particles by dehydration. The diameter of the dispersed particles was measured with a laser scattering particle analyzer. Particle diameter was depended on the applied pulse frequency and voltage, flow rate of the water glass, and water glass concentration. With increasing applied pulse frequency, the particle diameter and size distribution were decreased. Particles with 200 nm average diameter were produced at 1 kHz and 5.3 kV of applied pulse.