(353d) Surface Controlled Shape Design of Discotic Micro-Particles

Colloidal disks are one of the least studied anisotropic particles. They are vital to the understanding of discotic liquid crystals and can serve as model to study the behavior of red blood cells, soils and asphaltenes. Our research demonstrates theoretically and experimentally the principle to control the discotic morphology of wax particles with a smectic internal structure via their phase transition. We will introduce the capability to control the anisotropy of the resultant particles by using a mixture of surfactants and co-surfactants. Surfactant packing can control the surface interfacial curvature and set the elastic membrane shape in combination with surface freezing. A layered internal structure converts emulsions into disks. The final shape of the disks can be either biconcave or flat circular depending on the defect structure of the layers. We confirmed that the final aspect ratio of these flat disks can be controlled using different co-surfactant concentrations on the surface of the emulsions. This surface controlled organization of molecules offers novel routes for soft material design and fabrication.