含塞吩苯酯及雙苯酯側鏈液晶高分子之合成與性質研究

Abstract

本研究主要的目的是要合成含塞吩之側鏈液晶高分子，探討塞吩環對所合成化合物液晶行為的影響。本研究選擇液晶基係以塞吩環接上一個或兩個苯環為主要結構，以甲氧基或氰基為末端基，採酯基做連接基構成分子結構，並以聚矽氧烷為高分子主鏈，3至11個亞甲基單位為柔軟間距，所合成的單體經矽氫化反應接到聚矽氧烷主鏈上。合成所得之單體以核磁共振光譜儀、紅外光譜儀鑑定其結構，所有單體及聚合物皆以微差掃描卡及偏光顯微鏡測定液晶轉移溫度並鑑定液晶相。研究結果顯示第一、二系列單體和其聚合物皆沒有液晶相出現；而含氰基末端基的第三系列單體和聚合物出現層列型A相及向列型液晶相，第四系列單體和聚合物因具有低極性甲氧基末端基，只出現向列型液晶相。本研究所合成之液晶聚合物具有應用於高效能氣相層析之靜相材料的潛力。

The goal of this research is mainly focused on the synthesis of side-chain liquid crystalline polymers containing thiophene-based mesogens.Four series of new side-chain liquid crystalline polymers will be prepared according to carefully molecular design of polymer backbone,spacer,mesogen and end group.Polysiloxane is used as the polymer backbone.Three to eleven methylene units are used as flexible spacer. Thiophenyl benzoate and Thiophenyl 4-hydroxybiphenyl-4¢-carboxylate are designed for the mesogen,and a cyano and a methoxy are designed for the end groups.the prepared liquid crystal monomers are grafted onto the polysiloxane backbone via hydrosilation reaction.The obtained monomers and polymers are characterized by FT-IR,NMR and determined by DSC and optical polarizing microscope. In the first and second series of monomers and polymers which contain two rings do not present any mesophase.In the Third series which contain three aromatic rings and the cyano end group presnet respectively a smectic A phase and a nematic phase.The fourth series just present a nematic phase.The synthesized liquid crystalline polymers have potential applications in the field of stationary phase of column chromatography