Highly birefringent colloidal particles for tracer studies

We report on the preparation and characterization of highly birefringent, monodisperse colloidal particles with sizes between 100 nm and some micrometres made by emulsification of a reactive acrylate monomer in aqueous solution. Photopolymerization of the emulsion droplets in the liquid crystalline state results in particles with frozen orientational order. Particles that had not been polymerized have a higher effective birefringence than the polymerized particles at room temperature, as shown by measurements of the depolarized scattering intensity using quasi-elastic light scattering (QELS). We also present preliminary results showing that larger particles can be made to rotate with optical tweezers with circular polarization.