Title:
Nematic biaxiality in a bent-core material
Nematic biaxiality in a bent-core material
Author(s)
Yoon, Hyung Guen
Kang, Shin-Woong
Dong, Ronald Y.
Marini, Alberto
Suresh, Kattera A.
Srinivasarao, Mohan
Kumar, Satyendra
Kang, Shin-Woong
Dong, Ronald Y.
Marini, Alberto
Suresh, Kattera A.
Srinivasarao, Mohan
Kumar, Satyendra
Advisor(s)
Editor(s)
Collections
Supplementary to
Permanent Link
Abstract
The results of a recent investigation of the nematic biaxiality in a bent-core mesogen _A131_ are in apparent disagreement with earlier claims. Samples of mesogen A131 used in the two studies were investigated with polarized optical microscopy, conoscopy, carbon-13 NMR, and crossover frequency measurements. The results demonstrate that textural changes associated with the growth of biaxial nematic order appear at _149 °C. The Maltese cross observed in the conoscopic figure gradually splits into two isogyres at lower temperatures indicating phase biaxiality. Presence of the uniaxial to biaxial nematic phase transition is further confirmed by temperature trends of local order parameters based on 13C chemical shifts in NMR experiments. Frequency switching measurements also clearly reveal a transition at 149 °C. Differences between the two reports appear to be related to the presence of solvent, impurities, and/or adsorbed gases in samples of A131 used in the study of Van Le et al. _Phys. Rev. E 79, 030701 _2009__.
Sponsor
Date Issued
2010-05
Extent
Resource Type
Text
Resource Subtype
Article