臺灣博碩士論文加值系統

本實驗以 (S)-2-(6-methoxy-2-naphthly)propionic acid為起始物合成三系列具有methyleneoxy為連結基的旋光性酯類液晶材料，並探討其分子結構與誘電性液晶性質的關係。所有合成的旋光性材料I(m=8~12)、II(m=8~12)及III(m=8~12)均具有SmA*與SmC*兩種液晶相，隨著非旋光末端烷鏈長度’m’的增加，澄清點會隨著降低。
量測化合物I(m=10~12)、II(m=10~12)及III(m=10~12)的自發性極化值，最大值介於12.3 ~19.1nC/cm2。
比較化合物I(m=10)、II(m=10)及III(m=10)的傾斜角，發現隨著旋光末端烷鏈長度’n’的增加，傾斜角會隨之變小。傾斜角最大值介於25~30度。
總而言之，旋光末端烷鏈長度及非旋光末端烷鏈長度都會影響到液晶材料的物理性質。

Three homologous series of chiral esters derived from (S)-2-(6-methoxy-2-naphthly)propionic acid with methyleneoxy linking group were synthesized. The correlation between the molecular structure and the ferroelectric liquid crystal (FLC) property has been investigated.Three series of chiral materials I(m=8~12), II(m=8~12), and III(m=8~12), displayed enantiotropic mesophases of the SmA* and SmC* phases. The clearing points for the three series decrease with increasing of the nonchiral terminal chain length ‘m’.
The maximum Ps values of I(m=10~12), II(m=10~12), and III(m=10~12) vary from 12.3 to 19.1nC/cm2.
Comparing the tilt angles of I(m=10), II(m=10), and III(m=10), the maximum tilt angle values were in the range of 25~30 degrees. There is a decreasing tendency of tilt angle as increasing chiral chain length.

ACKNOWLEDGMENTS---------------------------------------------------------III
ABSTRACT----------------------------------------------------------------IV
中文摘要----------------------------------------------------------------VI
TABLE OF CONTENTS-------------------------------------------------------VII
LIST OF SCHEMES---------------------------------------------------------X
LIST OF TABLES----------------------------------------------------------XI
LIST OF FIGURES---------------------------------------------------------XII
CHAPTER 1 1
INTRODUCTION------------------------------------------------------------1
1.1 Overview------------------------------------------------------------1
1.2 Chiral Chiral Smectic Phases----------------------------------------1
1.2.1 Chiral Smectic A Phases-------------------------------------------1
1.2.2 Chiral Smectic C Phase (Ferroelectric phase)----------------------2
1.3 Motivation of study-------------------------------------------------9
CHAPTER 2---------------------------------------------------------------11
EXPERIMENTAL------------------------------------------------------------11
2.1 Preparation of materials--------------------------------------------11
2.1.1 Synthesis of 4-(4’-alkoxyphenyl)benzoic acids, I-1---------------12
2.1.2 Synthesis of 4-(4´-alkoxyphenyl)benzyl alcohols, I-2--------------14
2.1.3 Synthesis of alkyl (S)-2-(6-methoxy-2-naphthyl) propionates, I-3, II-3, and III-3 ---------------------------------------------------------------14
2.1.4 Synthesis of alkyl (S)-2-(6-hydroxy-2-naphthyl)propionates, I-4, II-4, and III-4 ---------------------------------------------------------------15
2.1.5 Synthesis of alkyl (S)-2-(6-(4-(4´-alkoxyphenyl)benzyloxy)-2- naphthyl)propionates, I-5, II-5, and III-5---------------------------------------16
2.2 Physical properties-------------------------------------------------17
2.2.1 Mesophase identification------------------------------------------17
2.2.2 Preparation of homogenous cells-----------------------------------17
2.2.3 Alignment of liquid crystals in SSFLC Cells-----------------------18
2.2.4 Spontaneous polarization measurement------------------------------18
2.2.5 Measurement of tilt angle-----------------------------------------19
CHAPTER 3---------------------------------------------------------------20
RESULTS AND DISCUSSION--------------------------------------------------20
3.1 Chemical structure identification-----------------------------------20
3.2 The effect of peripheral chain length for I(m=8~12) series----------29
3.2.1 Transition temperatures and mesomorphic properties----------------29
3.2.2 Switching behavior------------------------------------------------35
3.2.3 Spontaneous polarization (Ps)-------------------------------------38
3.3 The effect of peripheral chain length for II(m=8~12) series---------38
3.3.1 Transition temperatures and mesomorphic properties----------------39
3.3.2 Switching behavior------------------------------------------------45
3.2.3 Spontaneous polarization (Ps)-------------------------------------45
3.4 The effect of peripheral chain length for III(m=8~12) series--------49
3.4.1 Transition temperatures and mesomorphic properties----------------49
3.4.2 Switching behavior------------------------------------------------52
3.4.3 Spontaneous polarization (Ps)-------------------------------------52
3.5 Effect of alkyl chain length ‘n’ at chiral tail on the Ps values--59
3.6 Effect of alkyl chain length ‘n’ at chiral tail on the tilt angles-59
CHAPTER 4 ---------------------------------------------------------------62
CONCLUSIONS-------------------------------------------------------------62
REFERENCES--------------------------------------------------------------63

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