A method to produce reverse-mode polymer-dispersed liquid-crystal shutters

Reverse-mode operation shutters have been achieved by combining the techniq ues of the traditional means of making polymer-dispersed liquid crystals an d nematic curvilinear aligned phases. Nematic microemulsions, obtained by a thermally induced phase separation, have been photopolymerized in an exter nal force field. After the polymerization, films show 85% transmittance in the OFF state, while it decreases to less than 1% when an electric field of about 2 V mu m(-1) at 1 kHz is applied. The rise-time values, about 2 ms, are in the same range as those obtained with normal-mode polymer-dispersed liquid-crystal films. On the contrary, decay time shows longer values. (C) 1999 American Institute of Physics. [S0003-6951(99)03626-8].