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 pulsati ng electric field to a monolayer at the air-water interface. By using the pulsating electric field, a rather strong field can be applied mor e stably than by using a static one. Molecular orientations of LB film s of 10,12-pentacosadiynoic acid (PD) cadmium salt fabricated with the trough were measured by X-ray diffraction. It is shown that the macro scopic molecular orientation of polymerized diacetylene LB films can b e improved by applying the electric field. The effect of the electric field on the molecular orientations depends on the subphase temperatur e and the kinds of substrates.