Mueller Matrix Polarimetry on Cyanine Dye J -Aggregates

Cyanine dyes are known to form - and -aggregates in aqueous solutions. Here we show that the cyanine dye, S0271, assembles in water into vortex induced chiral -aggregates. The chirality of the -aggregates depends on the directionality of the vortex. This study utilised both conventional benchtop CD spectropolarimeters and Mueller matrix polarimetry. It was found that -aggregates have real chirality alongside linear dichroism and linear and circular birefringence. We identify the factors that are key to the formation of metastable chiral -aggregates and propose a mechanism for their assembly.