Carbon-13 NMR Study of Liquid Crystals

这项研究是物理化学实验计划的一部分，将使用碳13核磁共振来研究液晶的取向有序性。所采用的方法包括消除质子-质子耦合，在魔角附近快速旋转样品，减少碳-质子耦合，并使用傅里叶变换技术来解析不同碳原子的峰。用这种方法将研究几个体系，包括介晶核中的向列相液晶。铁电液晶侧链上取代基的作用与其自发极化有关。具有聚丙烯酸酯和聚硅氧烷骨架的侧链液晶聚合物的取向有序性将被研究。采用基于分子场理论的链序计算方法对实验结果进行分析。

This research, part of the Physical Chemistry Experimental Program, will use carbon-13 NMR to study orientational ordering of liquid crystals. The method to be used involves the removal of proton-proton couplings, rapid sample spinning near the magic angle and reduction of carbon-proton couplings, coupled with the use of Fourier transform techniques to resolve peaks of different carbon atoms. Several systems will be studied by this method including nematic liquid crystals in the mesogenic core. The effects of substituents in the side chain of ferroelectric liquid crystals will be correlated with their spontaneous polarization. Orientational ordering of side chain liquid crystal polymers with polyacrylate and polysiloxane backbones will be investigated. Chain ordering calculations based upon molecular field theory will be performed to analyze the experimental results.