DEVELOPMENT OF A SYSTEM FOR CHARACTERIZATION OF LINEAR AND NONLINEAR DIELECTRIC PROPERTY OF NANOMETRIC ORGANIC THIN FILM

本研究的目的是开发一套用于表征有机单层膜的线性和非线性介电性质的测量系统，并测量水表面单层膜的麦克斯韦位移电流(MDC)和二次谐波(SHG)。进一步地，基于核心单层模型的单层分析是本文的目的。因此，本研究是在研究人员提出的麦克斯韦位移电流测量思想的基础上进行的。研究人员使用棒状极性分子模型分析了有机单层膜的分子运动，假设分子的运动受玻尔兹曼统计规律的支配。他们从理论上推导了单分子膜的介电弛豫时间，并分析了手性和非手性单分子膜产生MDC的过程。他们还分析了单分子膜的相变，并用连续介质理论解释了混合单分子膜的手性相分离。得到了取向序参数1、2、3与MDC和SHG信号之间的关系。他们还测量了5CB液晶单分子膜的MDC和SHG。基于连续介质理论，分析了偶氮苯的构象变化和偶氮苯分子在混合单层体系中的分子运动所引发的液晶分子的进一步取向转变过程，并通过光学透过率和电容的同时测量讨论了液晶分子的运动。

The purpose of this investigation was to develop a measurement system used for the characterization of linear and nonlinear dielectric properties of organic monolayer films, and to measure Maxwell-displacement current (MDC) and Second Harmonics Generation (SHG) from monolayers on a water surface. Further to analyze monolayers based on a hardcore monolayer model was the purpose. Thus, this investigation has been carried out on the basis of the idea of Maxwell-displacement current measurement proposed by the investigators. The investigators analyzed the molecular motion of organic monolayer films using a rod-like polar molecular model, assuming the motion of molecules is ruled by the Boltzmann statistics. They theoretically derived dielectric relaxation time of monolayers and also analyzed the generation of MDC from chiral and achiral monolayers. They also analyzed the phase transition of monolayers and explained the chiral phase separation of mixed monolayers using a continuum theory. The relationship between the orientational order parameters, i.e., 1st 2nd and 3rd orientational order parameters, and the MDC and SHG signals were obtained. They also measured the MDC and SHG from 5CB liquid crystal monolayers. Further orientational transition process of LCs triggered by conformational change of azobenzene and the molecular motion of azobenzenes in mixed monolayer systems were analyzed based on a continuum theory, and the motion of LCs was discussed based on the simultaneous measurement of optical transmittance and the capacitanace.