MEASUREMENT OF THE DISPLACEMENT CURRENT ACROSS MONOLAYERS AT THE AIR-WATER-INTERFACE USING KUHN-TYPE LB FILM APPARATUS

A number of methods have been developed to investigate the physical pr operties of monolayers formed at the air-water interface. Among them, the displacement current method is appropriate for the investigation o f the dynamic behavior of monolayers. The measuring system of displace ment current method was constructed at home-made Kuhn type LB depositi on apparatus using aluminum plate electrode. The currents induced by t he dynamic motion of molecules were measured when the molecules were p ressed by barrier. To verify the measuring system, we used 4-octyl-4'- (5-carboxy-penta-methyleneoxy) azobenzene molecules which has two rema rkable variations of surface pressure of monolayer at the air-water in terface. We can detect the two peaks of displacement currents which sh ows that the orientations of molecules are changed greatly at the stat e of these two remarkable changes of surface pressure.