Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5410155 | Journal of Molecular Liquids | 2016 | 6 Pages |
Abstract
We present systematic experimental data on high resolution measurements of temperature dependence of optical birefringence (În) in a binary liquid crystalline system comprising calamitic 4-cyano-4â²-octyloxybiphenyl (8OCB) and a hockey stick-shaped compound, 4-(3-decyloxyphenyliminomethyl) phenyl 4-decyloxycinnamate (SF7). The hockey stick-shaped mesogen shows a smectic A (SmA) phase in addition to two polymorphic tilted smectic phases. From an analysis of the În data, a quotient Q(T) has been derived which exhibits power law divergences both above and below the smectic A-nematic (SmA-N) phase transition. A noticeable shrinkage in width of the nematic range has been observed for a small increase in concentration of the angular mesogenic dopant. In the vicinity of the SmA-N phase transition, the values of effective critical exponent (αâ²), characterizing the critical fluctuation at this transition, have appeared to be in between those predicted by the 3D-XY and tricritical hypothesis. Furthermore, with increasing hockey stick-shaped molecular concentration, the SmA-N transition shows a tendency to be driven towards a first order nature.
Related Topics
Physical Sciences and Engineering
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Physical and Theoretical Chemistry
Authors
Susanta Chakraborty, Anish Chakraborty, Malay Kumar Das, Wolfgang Weissflog,