Abstract
Using a current-measuring technique, we investigated the abrupt change of a current observed at the liquid-to-solid phase transition in a current-area (I-A) isotherm of a fatty acid monolayer at the air/water interface. The change occurred when an electrode suspended in air was not electrically shielded. It was found both experimentally and theoretically that the behavior of the monolayer at the edge of the trough plays a very important role in the abrupt change described above.