Conducting defects in Langmuir-Blodgett films of cadmium stearate

Abstract

Abstract Langmuir-Blodgett films of cadmium stearate were prepared by the vertical dipping method, and conducting defects were observed by the copper decoration technique. The density of conducting defects was low for the films transferred at surface pressures less than 10 mN m −1 , and it increases with surface pressure, especially at more than 30 mN m −1 . Surface pressure-area isotherms were measured in a Langmuir trough. At the intermediate stage of compression of a Langmuir film, the surface pressure was kept at a certain value for 40 min. An appreciable decrease in the area was observed during the period of constant pressure. The apparent decrement in the molecular area increases gradually with pressure in the low pressure range, but it increases sharply with pressure above 30 mN m −1 . It is considered that the Langmuir film collapses partially at high surface pressures, and conducting defects are produced when the collapse of the Langmuir film is brought about.