Colloidal alphabet soup: Monodisperse dispersions of shape-designed LithoParticles

Abstract

By lithographically mass-producing exotic colloids, or " LithoParticles", we generate unique model systems that have not been previously obtained either through self-assembly or bottom-up growth processes. Customizable control over the features of LithoParticles is achieved at the micron and submicron scales using automated stepper lithography, providing high-throughput production in combination with exquisite fidelity of the shapes. Billions of copies of colloidal fluorescent polymeric particles comprising all 26 letters of the Latin alphabet are stably dispersed in a liquid, yielding multicolored "colloidal alphabet soup". Multilayer hybrid polymer particles with complex three-dimensional shapes and different internal compositions demonstrate the full potential of the approach. Colloidal LithoParticles in solution exhibit significant Brownian motion driven by thermal energy, making them excellent model systems for exploring new phenomena, such as phase transitions, jamming, and self-assembly, in which the shapes of the particles play a key role. © 2007 American Chemical Society.