Orientational order in smectic liquid-crystalline phases of amphiphilic diols.
Orientational order in smectic liquid-crystalline phases of amphiphilic diols.
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两亲二醇的近晶液晶相的取向顺序。
DOI：
10.1063/1.1943972
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
A. Saipa
中科院分区：
文献类型：
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作者：
F. Giesselmann;R. Germer;A. Saipa
利用小角和广角x射线散射研究了两亲性2-（反式-4-n-烷基环己基）-丙烷-1,3-二醇的热致近晶相，并从散射剖面中提取了近晶（双）层间距、取向序参数P(2)和P(4)、取向分布函数和层内相关长度的值。辛基同源物的结果表明，这些同晶相具有高度的同晶一维平移有序和极低的取向有序，其序参量（P(2)约为0.56）远低于非两亲同晶相。这种结合在热致近晶中非常罕见，很可能源于末端二醇基团之间的分子间氢键，这似乎是这些两亲动物形成热致近晶结构的特定驱动力，并导致了一种微相偏析。即使在没有溶剂的情况下，两亲性中原的液晶排列也接近于在溶致液晶中发现的所谓的整齐肥皂的结构。
The thermotropic smectic phases of amphiphilic 2-(trans-4-n-alkylcyclohexyl)-propane-1,3-diols were investigated by means of small- and wide-angle x-ray scattering and values of the smectic (bi-)layer spacing, the orientational order parameters P(2) and P(4), the orientational distribution function as well as the intralayer correlation length were extracted from the scattering profiles. The results for the octyl homolog indicate that these smectic phases combine a very high degree of smectic one-dimensional-translational order with remarkably low orientational order, the order parameter of which (P(2) approximately 0.56) is far below those values typically found in nonamphiphilic smectics. This combination, quite exceptional in thermotropic smectics, most likely originates from the intermolecular hydrogen bonding between the terminal diol groups which seems to be the specific driving force in the formation of the thermotropic smectic structure in these amphiphiles and leads to a type of microphase segregation. Even in the absence of a solvent, the liquid-crystalline ordering of the amphiphilic mesogens comes close to the structure of the so-called neat soaps, found in lyotropic liquid crystals.