Single-step synthesis of three-dimensional particles using non-uniform UV polymerization

Polymer-based microparticles are increasingly utilized in a range of biotechnology application. There is growing evidence that microparticle shape is an important parameter governing its functionality. Yet, there currently exists no straightforward method to controllably synthesize a large number of highly three-dimensional (3D) microparticles. In this thesis, we develop a one-step two-dimensional (2D) stop-flow lithography method that exploits the non-uniformity of the polymerizing ultraviolet (UV) light, UV adsorption by opaque nanoparticles in the precursor solution, and discontinuous photomask patterns, to make highly curved 3D microparticles. We investigate the microparticle shape dependence on each parameter by independently tuning the field and focus of the UV light, adding opaque magnetic nanoparticles to the precursor solution, and using a variety of photomask patterns.We also perform numerical simulations of oxygen concentration and monomer conversion in the microfluidic channel, to predict the particle shape. By simplifying the synthesis of high curvature 3D particles with 3D surface features and branched structures, our method may lead to the expanded use of microparticles in research and in industry.