An extensive analysis of isodesmic assembly in dilute solutions of two lyotropic chromonic liquid crystal systems

ABSTRACT

Lyotropic chromonic liquid crystal (LCLC) molecules spontaneously assemble into anisotropic structures. Here, the behaviour of LCLC molecules in aqueous solutions is investigated to test whether the assembly process in two different systems is isodesmic. Dilute solutions are required for such a test, so this work focuses on changes in the UV and visible absorption spectra for DSCG and SSY solutions with concentrations no greater than 0.5 wt%, which are always in the isotropic phase. Unlike prior investigations of these systems, the complicated absorption spectra are decomposed into simple absorbance peaks prior to analysis. In addition, two slightly different models of isodesmic assembly and two different analysis methods of the absorption spectra are utilised. Not all of the new experimental results are consistent with prior work, but in the end the analyses confirm that an isodesmic process is an appropriate model for these LCLC systems.

Graphical abstract

KEYWORDS:

• Lyotropic chromonic liquid crystal (LCLC)
• disodium cromoglycate (DSCG)
• Sunset Yellow (SSY)
• molecular aggregation

Acknowledgments

The Authors would like to thank Heinz Kitzerow for illuminating discussions.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.

Additional information

Funding

This research was funded by the President of Paderborn University (Post-doc Scholarship).