Study on the dynamic behavior of Langmuir films at the air-water interface by a displacement current measuring method

The measuring system of displacement current measuring method was constructed at home-made Kuhn type LB (Langmuir-Blodgett) deposition apparatus using electrodes. Solutions of 4-octyl-4′-(5-carboxy-pentamethyleneoxy) azobenzene molecules (8A5H) and stearic acid (C18) were spreaded at the air-water interface respectively, and the currents induced by the dynamic behavior of molecules were measured when the molecules were pressed by barrier. Two distinct peaks of displacement currents were attained which show that the orientations of molecules were changed greatly at these states. The reversibility of displacement currents by compression and expansion was obtained from 8A5H molecules.