(62f) Synthesis of Monodisperse Polymer Particles by Photopolymerization in Flow Micro-Reactors

In recent years, microdroplet-based processes are finding increasing applications in existing and emerging technologies. In each of these cases, a solution microdroplet as a micro-reactor undergoes liquid to solid phase transformation. The property of the final solid phase depends on a number of time-dependent physical and chemical transformations occurring in the microdroplets. Highly monodisperse multiacrylate microspheres of diameters of 5-50 ìm, containing nanoparticles and additives, were prepared by UV-radiation photopolymerization. The microdroplets, with size fluctuations of less than 0.01%, with different monomer concentration were generated with a vibrating orifice aerosol generator (VOAG). The properties of the resulting particles (morphology, size, size distribution, and surface characteristics) were measured by scanning electron microscopy and optical microscopy. The resulting particles were monodisperse with a coefficient of variation (ratio of the standard deviation of the particles to the mean particle diameter) of 1% or less. The solid microparticles may be tuned in size by varying reaction procedures. The results of our experiments show that tailored microspheres (e.g., multicomponent, layered, and with nanoparticle inclusions) of highly reproducible size and physical characteristics can be produced, and the morphology of the final solid polymer particles can controlled by the initial droplet size and composition as well as through the reaction conditions. The results suggest possibility of preparing microparticles of various compounds with reproducible physical properties and functions through adding desired components, such as salt, additives and drugs et al. It is also possible to produce monodisperse multicomponent particles, spherical microcapsules, and micro-resonators