Maxwell displacement current across monolayers and its application to monolayer-film devices

The dielectric behavior of monolayers have been investigated by means of the Maxwell-displacement-current (MDC) technique, that allows molecular motions in monolayer films to be probed without destroying monolayer films. The orientational ordering of polar molecules is defined as S=⟨cosθ⟩, where θ is the tilt angle of polar molecules away from the normal direction to the monolayer, and the differential equation representing the transient behavior of polar molecules is derived on the basis of the Brownian motion equation of polar molecules by Debye. The equation representing the Maxwell displacement current across monolayers is presented for the first time. We examined the MDC across monolayers of 4-cyano-4´-5-alkyl-biphenyl (5CB) Langmuir film due to the piezo-electrical effect was examined, and the vertical component of dipole moment of the molecules was determined. Finally we discussed the application of MDC flowing across monolayers containing azo-dyes to monolayer-film devices