Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture

碩士 === 大同大學 === 化學工程學系(所) === 100 === A few of liquid crystal materials exhibiting blue phases have been reported in a single compound, moreover, the blue phases in the materials possess a very small temperature range (calc. 1-2℃), mainly because of the blue phases are frustration phases. Thus, i...

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Main Authors: Yu-Wen Chu, 朱裕文
Other Authors: Shune-Long Wu
Format: Others
Language:en_US
Published: 2012
Online Access:http://ndltd.ncl.edu.tw/handle/60690138142322492394
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spelling ndltd-TW-100TTU050630032015-10-13T21:22:40Z http://ndltd.ncl.edu.tw/handle/60690138142322492394 Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture 探討旋光基烷鏈為支鏈及燕尾的燕尾形態的液晶材料以及混合液晶材對藍相生成的影響 Yu-Wen Chu 朱裕文 碩士 大同大學 化學工程學系(所) 100 A few of liquid crystal materials exhibiting blue phases have been reported in a single compound, moreover, the blue phases in the materials possess a very small temperature range (calc. 1-2℃), mainly because of the blue phases are frustration phases. Thus, in order to find more of blue phase materials and shed light on the relationship between molecule structure and the formation of blue phases, in this work, we designed and synthesized eight series of compounds derive from optically active alcohol, according to the previous results from our laboratory, for the investigation. The results of the works are divided into two parts for discussion, and the results for discussion are in term of the effect of (i) achiral terminal alkyl chain length (m) of the materials, (ii) chiral alkyl chain length (n) of the materials, (iii) chiarl terminal swallow-tailed alkyl chain length (p, q) and (iv) the achiral terminal alkyl chain directly connected to the benzene ring with ether (-O-) linking group, and achiral terminal alkyl chain connected to the benzene ring of the materials, on the generation of blue phase liquid crystals.Eight series of the compounds for the study with the general formulas are depicted below.The third part of the works was to investigate whether the binary mixture of the blue phase materials could enhance the thermal stability of the blue phase. The corresponding molecular structures of the target compounds for the binary mixture study are depicted below: The results from the study of two series of novel chiral compounds derived from derived from optically active branched alkyl alcohols, which was previously prepared by the treatment of (S)-propylene oxide with various branched alkyl chain, show that chiral compounds I(O, m, n, p, q) , depending on the molecular structure, various mesomorphic phases: BP, N*, TGBA*, SmA* and SmC* phases can be found. The appearance of frustrated phases (BP and TGBA* phases) indicate that all compounds possess high chirality. The results shows that chiral compounds II(-, m, n, p, q) display only BP and N* phases, indicating that the alkyl group directly attaches to the phenyl ring without ether (-O-) linking group could depress the formation of higher order smectic phases. In general, compounds that having alkyl group directly attaches to the phenyl ring without ether (-O-) linking group are easier to generate the stable blue phases as compared to that with ether (-O-) linking group. The investigation of the binary mixtures on the formation blue phase demonstrates that the mixtures have no any significant enhancement on the thermal stability of the blue phase. In conclusion, our results show that the blue phase materials can be designed and synthesized, however, the temperature range of blue phase in this work only reaches as large as 13.57℃. Comparison of two series, I(O, m, n, p, q) and II(-, m, n, p, q), of compounds, it can be found that compounds having alkyl group directly attaches to the phenyl ring without ether (-O-) linking group have wider BP temperature range than compounds having the alkyl group attaches to the phenyl ring with ether (-O-) linking group. The results of binary mixtures of the blue phase materials also indicate that the enhancement of temperature range of blue phase by the mixing method is not feasible. Shune-Long Wu 吳勛隆 2012 學位論文 ; thesis 95 en_US
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description 碩士 === 大同大學 === 化學工程學系(所) === 100 === A few of liquid crystal materials exhibiting blue phases have been reported in a single compound, moreover, the blue phases in the materials possess a very small temperature range (calc. 1-2℃), mainly because of the blue phases are frustration phases. Thus, in order to find more of blue phase materials and shed light on the relationship between molecule structure and the formation of blue phases, in this work, we designed and synthesized eight series of compounds derive from optically active alcohol, according to the previous results from our laboratory, for the investigation. The results of the works are divided into two parts for discussion, and the results for discussion are in term of the effect of (i) achiral terminal alkyl chain length (m) of the materials, (ii) chiral alkyl chain length (n) of the materials, (iii) chiarl terminal swallow-tailed alkyl chain length (p, q) and (iv) the achiral terminal alkyl chain directly connected to the benzene ring with ether (-O-) linking group, and achiral terminal alkyl chain connected to the benzene ring of the materials, on the generation of blue phase liquid crystals.Eight series of the compounds for the study with the general formulas are depicted below.The third part of the works was to investigate whether the binary mixture of the blue phase materials could enhance the thermal stability of the blue phase. The corresponding molecular structures of the target compounds for the binary mixture study are depicted below: The results from the study of two series of novel chiral compounds derived from derived from optically active branched alkyl alcohols, which was previously prepared by the treatment of (S)-propylene oxide with various branched alkyl chain, show that chiral compounds I(O, m, n, p, q) , depending on the molecular structure, various mesomorphic phases: BP, N*, TGBA*, SmA* and SmC* phases can be found. The appearance of frustrated phases (BP and TGBA* phases) indicate that all compounds possess high chirality. The results shows that chiral compounds II(-, m, n, p, q) display only BP and N* phases, indicating that the alkyl group directly attaches to the phenyl ring without ether (-O-) linking group could depress the formation of higher order smectic phases. In general, compounds that having alkyl group directly attaches to the phenyl ring without ether (-O-) linking group are easier to generate the stable blue phases as compared to that with ether (-O-) linking group. The investigation of the binary mixtures on the formation blue phase demonstrates that the mixtures have no any significant enhancement on the thermal stability of the blue phase. In conclusion, our results show that the blue phase materials can be designed and synthesized, however, the temperature range of blue phase in this work only reaches as large as 13.57℃. Comparison of two series, I(O, m, n, p, q) and II(-, m, n, p, q), of compounds, it can be found that compounds having alkyl group directly attaches to the phenyl ring without ether (-O-) linking group have wider BP temperature range than compounds having the alkyl group attaches to the phenyl ring with ether (-O-) linking group. The results of binary mixtures of the blue phase materials also indicate that the enhancement of temperature range of blue phase by the mixing method is not feasible.
author2 Shune-Long Wu
author_facet Shune-Long Wu
Yu-Wen Chu
朱裕文
author Yu-Wen Chu
朱裕文
spellingShingle Yu-Wen Chu
朱裕文
Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture
author_sort Yu-Wen Chu
title Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture
title_short Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture
title_full Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture
title_fullStr Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture
title_full_unstemmed Study on Formation of Blue Phases from the Branched Alkyl Chain and Swallow-Tailed Chiral Liquid Crystals and the Binary Mixture
title_sort study on formation of blue phases from the branched alkyl chain and swallow-tailed chiral liquid crystals and the binary mixture
publishDate 2012
url http://ndltd.ncl.edu.tw/handle/60690138142322492394
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