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Updated: Jun 16, 2026

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
Aggregation properties of the chromonic liquid crystal benzopurpurin 4B
Christopher B McKitterick1, Nathaniel L Erb-Satullo, Nicholas D LaRacuente
1Department of Physics & Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, USA.
Abstract:
Optical polarization, absorption, and scattering studies along with confocal microscopy reveal that Benzopurpurin 4B forms aggregates of micrometer size at very low concentrations in aqueous solution. A chromonic liquid crystal phase is stable at room temperature down to concentrations as low as 0.4 wt %, which can only be possible if the aggregates contain an ample amount of water. The kinetics of aggregate formation are extremely slow, with changes going on for days before equilibrium is reached. The stacking free energy change is estimated to be 10.3 +/- 0.4 k(B)T, which is in the higher range of values for recently studied chromonic liquid crystals. However, the very low concentration of the liquid crystal phase puts it in a different class, probably more similar to Scheibe or Jelly aggregates than the typical chromonic systems that are formed by simple stacks of molecules.
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