Study of relaxation processes in monomolecular films by the step compression experiment

Abstract

Maxwell's displacement current flowing through a metal electrode/air gap/Langmuir monolayer was detected. MDC experimental results obtained during a step compression mode are presented and contrasted with the Debye-Brown rotational model. As an alternative approach a theoretical model based on an analogy with a nonideal gas of polar molecules is derived from Lagrange's equation of motion.

Analysis of mechanically induced processes in the Langmuir film

“…with parameters a = 0.4 kg À1 , b = 0.9 s À1 and n = 7 [15]. These theoretical calculations satisfactorily fit the experimental dependencies (Fig.…”

“…The change of orientational polarization vector can be expressed as Maxwell's displacement current flowing through the monolayer. As we showed in our previous studies [15] the current flowing in the outer circuit can be expressed as a time change of the induced charge…”

“…The latter one consists of mean value i/2k B T, where i is the degree of freedom (constant for given temperature T; disappear by time derivation) and its change 1=2 ð Þmṙ 2 . Potential energy was chosen in the Buckingham potential form for mutual intermolecular interactions (verified for continual compression [15]) and the Born-Mayer form of repulsive potential (exp-potential) for the layer-barrier interaction.…”

“…The potential energy for calculations was determined according to our previous model of the monolayer [15]. The mutual pair interaction between molecules consists of twobody dipole-dipole interaction and semi-empirical Buckingham's modified potential [16].…”