Publication Title

Physical Review E

Publication Date

10-2009

Document Type

Article

DOI

10.1103/PhysRevE.80.041703

Keywords

Chromonic Mesophases, Liquid Crystals, Surfactant, Micelles, Growth, Behavior, Systems, Phase, Dye

Disciplines

Physics

Abstract

The dye sunset yellow (SY) forms columnar aggregates via π-π stacking in aqueous solutions. These aggregates develop orientational and translational order at elevated concentrations to exhibit the nematic (N) and columnar (C) mesophases. Positional-order correlation lengths of the aggregates in the directions parallel and perpendicular to the stacking direction were measured as functions of temperature, concentration, and ionic content of solutions with synchrotron x-ray scattering in magnetically aligned samples. Average length of aggregates (i.e., the number of SY molecules in an aggregate) grows monotonically with concentration while their effective transverse separation decreases. The scission energy, E, determined from the Arrhenius thermal evolution of the longitudinal correlation length, is found to be 4.3±0.3 kBT and 3.5±0.2 kBT, in the N and C phases, respectively. Temperature and concentration dependence of E suggests that chromonic aggregation is not an isodesmic process. The aggregate length decreases with decreasing pH when HCl is added to the solution.

Comments

Copyright 2009 American Physical Society. Available on publisher's site at http://dx.doi.org/10.1103/PhysRevE.80.041703.


Included in

Physics Commons

Share

COinS