Development of a New Technique of Analyzing the Liquid Crystal Interface Reorientation Dynamics using Reflection FT-IR Time-Resolved Spectroscopy

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In this study, we have developed two new spectroscopic techniques, both with spacial and temporal resolution, in order to analyze the liquid crystal reorientation dynamics at the substrate surfaces.1.First, in order to analyze the elementary segmental processes of liquid-crystalline molecules during their electric-field induced reorientational transition, we have developed a new step-scan FT-IR time-resolved spectroscopy (FT-IR TRS) with 200ns time-resolution.Applicability of this new techniques has been demonstrated for nematic liquid crystals and for ferrolelectric smectic liquid crystals.2.To improve the spacial resolution and make it possible to analyze the liquid-crystal's surface reorientation dynamics, we have also developed a new time-resolved, polarization-modulated spectroellipsometry system (PMSE). This system, with 100nm spacial resolution and 20mus time-resolution, has enabled us to quantitatively analyze the surface anchoring effect and the director reorientation dynamics of liquid crystals in the very vicinity of substrate surfaces.By developing these new spectroscopic techniques, we have been able to open up a new field of dynamic analysis of liquid crystals that can penetrate into the detailed submolecular mechanisms of the field-induced reorientational transition in both nematic and smectic liquid crystals. The results obtained in this study are expected to be able to contribute to the further development of liquid crystal display devices.