Electrically-modulated variable permeability liquid crystalline polymeric membrane

Side chain liquid crystalline polysiloxane was synthesized and the effects of the DC electric field strength and the AC electric field frequency of an applied transmembrane field on membrane permeability were investigated. In this paper, the synthesis method of poly(methyl p-propyloxyphenyl, p-methoxy benzoate siloxane) and permeation data of p-aminoacetophenone through this polymer at 5°C are presented. Membrane permeability was observed to increase with increasing field strength and decrease with increasing frequency. Utilizing DC electric field, 28-fold increase in membrane permeability was obtained with a field strength of 4,200 V/cm. At a field strength of 4,900 V/cm, a 26-fold range in permeation rate was obtained between 0.001 Hz and 10 KHz. The response times required to achieve new steady state fluxes after changing frequency at 4,900 V/cm were observed to be nearly instantaneous in contrast to those observed on changing the DC electric field strength.