(A) study on synthesis and properties of new photopolymer with chalcone groups for retarder film

다국어 초록 (Multilingual Abstract)

In this study thesis, new polymaleimides containing chalcone unit in side chain were synthesized and characterized, and their controllability of reactive mesogen liquid crystal alignment on photoalignment surfaces were investigated. The new polymaleimides containing chalcone unit in side chain were prepared by esterification of Polymaleimides with hydroxyl group and three kinds of chalcone groups. The photopolymers with para, meta, and ortho position of carboxyl acid in the chalconyl group have the same to alkyl spacer length(C=6) introduced between main chain and chalconyl moiety. These photopolymers were characterized by FT-IR, 1H-NMR, UV-VIS and their properties were evaluated by solubility, thermal stability and LC alignment. Solubility of all polymers were shown similar that good soluble at general organic solvent such as THF, MEk but poor soluble in methanol, ethanol such as alcoholic solvent. The thermal stability of photopolymers was confirmed by the glass transition temperature of 79-91 ℃, decomposition temperature of 335-387 ℃, respectively. Para position of photopolymer was shown highest thermal stability. The UV absorption peak about 310-315 nm decreases abruptly in intensity in the early and then intensity decreases more slowly with increasing energy exposure by induced photodimerization. The pretilt angle generated was about 0.06-3.00o by polarized UV irradiation. These photopolymers were revealed not only high sensitivity but also superior alignment properties to the 50 mJ/cm2 of LPUV exposure energy. The alignment of photopolymers strongly depended on the substituted position of chalcone derivatives and that increase in the order PM6-m-ChF ≥ PM6-p-ChF ≫ PM6-o-ChF. Nonalignment ratio rapidly decreased at 40 mJ/cm2. Whereas PM6-o-ChF was measured over 42 % nonalignment ratio at all point. These results suggested that the higher sensitivity and alignment properties of PM6-m-ChF and PM6-p-ChF resulted from efficient molecular position of chalcone units in the photopolymers by to the irradiated direction of LPUV light used in this work. Through commercial applicability for patterned retardation film, it is confirmed that PM6-m-ChF shows an actual POM image of an excellent multi-domain alignment film that has been superior aligned by a aligned layer. It also was identified that PM6-m-ChF exhibited the enough possibility of commercial application for patterned retardation film through the multi-domain alignment properties and evaluation of non-alignment ratio. Despite that photoalignment film for practical application requires high alignment sensitivity under the 20 mJ/cm2 in order to apply the practical process, all photopolymers must be considerably the attractive materials for applicable to new display, including a patterned retarder film for 3D displays, because the high thermal stability and control of various process variable can be easily enhanced the photoalignment.

목차 (Table of Contents)

• Contents
• ABSTRACT i
• LIST OF TABLES vi
• LIST OF FIGURES vi
• 1. INTRODUCTION 1
• 1-1. Background of Photoalignment 1
• 1-2. Mechanisms of Photoalignment 4
• 1-3. Researches Objectives 6
• 2. EXPERIMENTAL 12
• 2-1. Raw Materials 12
• 2-2. Synthesis 15
• 2-2-1. Synthesis of poly hydroxyhexanoyl maleimide 15
• 2-2-2. Synthesis of 4-fulorochalconyl-x'-oic acid 16
• 2-2-3. Synthesis of poly (4-fulorochalconyl-x'-oxy)alkanoyloxyhexanoyl
• maleimide 17
• 2-3. Process 18
• 2-3-1. LC Cell process 18
• 2-3-2. Retarder film process 19
• 2-3-3. Multi-domain 20
• 2-4. Measurement 22
• 3. RESULTS AND DISCUSSION 23
• 3-1. Characteristics 23
• 3-1-1. Characteristic of the poly hydroxyhexanoyl maleimide 23
• 3-1-2. Characteristic of the 4-fulorochalconyl-x'-oic acid 25
• 3-1-3. Characteristic of the poly (4-fulorochalconyl-x'-
• oxy)alkanoyloxyhexanoyl maleimide 27
• 3-2. Thermal properties of the poly (4-fulorochalconyl-x'-
• oxy)alkanoyloxyhexanoyl maleimide 31
• 3-3. Optical Properties of the poly (4-fulorochalconyl-x'-
• oxy)alkanoyloxyhexanoyl maleimide 33
• 3-3-1. UV-VIS 33
• 3-3-2. Order parameter 36
• 3-4. Process of the poly (4-fulorochalconyl-x'-oxy)alkanoyloxyhexanoyl maleimide 38
• 3-4-1. Pretilt angle 38
• 3-4-2. POM image 40
• 3-4-3. Multi-domain 43
• 4. CONCLUSIONS 45
• REFERENCES 47