CONTROL OF MOLECULAR ORIENTATIONS BY A PULSATING ELECTRIC-FIELD APPLIED TO A MONOLAYER AT THE AIR-WATER-INTERFACE

We have made a Langmuir-Blodgett (LB) trough which can apply a pulsating electric field to a monolayer at the air-water interface. By using the pulsating electric field, a rather strong field can be applied more stably than by using a static one. Molecular orientations of LB films of 10,12-pentacosadiynoic acid (PD) cadmium salt fabricated with the trough were measured by X-ray diffraction. It is shown that the macroscopic molecular orientation of polymerized diacetylene LB films can be improved by applying the electric field. The effect of the electric field on the molecular orientations depends on the subphase temperature and the kinds of substrates.