Kapernaum Nadia, Giesselmann Frank
Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Dec;78(6 Pt 1):062701. doi: 10.1103/PhysRevE.78.062701. Epub 2008 Dec 8.
A procedure to obtain the smectic translational order parameter Sigma from the temperature-dependent intensity I of the fundamental (001) smectic layer peak, observed in small-angle x-ray scattering experiments, is presented. We report results obtained with this procedure on the smectic-A or chiral smectic-A phases of six different liquid crystals, among them a "de Vries"-type 2-{4'-[1'',1''-dihydro-2''-(2''-perfluorobutoxyperfluoroethoxy)- perfluoroethoxy]}phenyl-5'-octylpyrimidine(3M8422) and the antiferroelectric R-4-(1-methylheptyloxycarbonyl)phenyl-4'-octloxybiphenyl-4-carboxylate (MHPOBC) materials. The smectic order parameters obtained are in the range between 0.5 and 0.9. For the "de Vries"-type 3M 8422 we found remarkably high values of Sigma in the order of approximately 0.9.
本文提出了一种从在小角X射线散射实验中观察到的、与温度相关的基本（001）近晶层峰强度I获取近晶平移序参量西格玛（Sigma）的方法。我们报告了用该方法在六种不同液晶的近晶A相或手性近晶A相上得到的结果，其中包括“德弗里斯”型的2-{4'-[1'',1''-二氢-2''-(2''-全氟丁氧基全氟乙氧基)-全氟乙氧基]}苯基-5'-辛基嘧啶（3M8422）以及反铁电的R-4-(1-甲基庚氧基羰基)苯基-4'-辛氧基联苯-4-羧酸酯（MHPOBC）材料。得到的近晶序参量在0.5到0.9之间。对于“德弗里斯”型的3M 8422，我们发现西格玛（Sigma）的值非常高，约为0.9 。
