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Study of smectic layer liquid crystal formed by rod-like polymers arranged their molecular terminals regularly in space

分子末端空间规则排列的棒状聚合物形成近晶层液晶的研究

基本信息

批准号：
17350104
负责人：
KAWAUCHI Susumu
金额：
$ 9.47万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

Polysilanes having optically active side-chain exhibit rod-like configuration. They forms clear thermotropic-cholesteric liquid crystal when their molecular weights are relatively small, while they show smectic phase under cholesteric liquid crystal phase when molecular weight distribution is narrow (Mw/Mn < 1.1) and their smectic layer distance corresponds to the molecular length of polysilane. In this study, we mixed two samples with different molecular weights to observe behavior of smectic layers. As a result, we found that smectic phase is unstable when difference of the molecular weights is small, while two smectic phase is separated when difference of the molecular weights is large.Additionally, we prepared a diblock copolymer composed of polystyrene (PS) and side-chain liquid crystal polymer (LCP) by atom transfer radical polymerization. The weight fraction of the PS segment is 0.22, resulting in a microsegregated structure with PS cylinders hexagonally packed in a matrix of LCP, which forms smectic A, nematic and isotropic phases in order of increasing temperature. Shear flow at nematic temperatures orients well the PS microcylinders, as well as the nematic mesogens of the LCP in the velocity direction. A high degree of orientation of 0.95 is attained for microcylinders while the orientational order parameter of the nematic LC is around 0.5. Interestingly, the nematic LC mesogens recover their initial orientation upon cooling after they have lost the orientational order in the isotropic melt. This spontaneous orientation shows that PS cylinders whose orientation is strongly sustained with a temperature variation acts as an anchoring substrate for the nematic mesogens.

具有光学活性侧链的聚硅烷表现出棒状构型。当分子量较小时，它们形成清晰的热致液晶，而当分子量分布较窄（Mw/Mn < 1.1）时，它们在热致液晶相下呈现近晶相，近晶层间距与聚硅烷的分子长度相对应。在这项研究中，我们混合了两种不同分子量的样品，以观察近晶层的行为。结果表明，近晶相在相对分子质量差较小时不稳定，而在相对分子质量差较大时，近晶相分离。此外，我们还通过原子转移自由基聚合法制备了聚苯乙烯（PS）和侧链液晶聚合物（LCP）的嵌段共聚物。PS链段的重量分数为0.22，导致微偏析结构，其中PS圆柱体以六角方式填充在LCP基质中，其按温度升高的顺序形成近晶A相、非晶相和各向同性相。剪切流在100 ℃的定向以及PS微柱，以及在速度方向上的LCP的介晶。一个高的取向度为0.95的微柱，而取向序参量的CNOLC是0.5左右。有趣的是，在各向同性熔体中失去取向顺序后，在冷却时，CNOLC介晶恢复其初始取向。这种自发取向表明，PS圆柱体的取向是强烈持续与温度变化作为锚定基板的介晶。

项目成果

期刊论文数量（0）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Thermotropic Liquid Crystals of Main-Chain Polyesters Having a Mesogenic 4,4'-Biphenyldicarboxylate Unit.15. Two Distinct Types of Orientation Processes Observed in Uniaxially Elongated Smectic LC Melt

具有介晶4,4-联苯二甲酸单元的主链聚酯的热致液晶。15．

DOI：
发表时间：
2005
期刊：
Macromolecules 38
影响因子：
0
作者：
Kensuke Osada;Masao Koike;Hirotaka Tagawa;Shin-ichiro Hunaoka;Masatoshi Tokita;Junji Watanabe
通讯作者：
Junji Watanabe

PL Scattering and Synchrotron Radiation Wide-Angle X-ray Diffraction Studies on Smectic Liquid Crystal Formation of Main-Chain Polyester

主链聚酯近晶液晶形成的PL散射和同步辐射广角X射线衍射研究