Polymer particles are finding increasingly important applications in both industry and academia, for example acting as specialty additives to coatings, pharmaceuticals, and personal care products. An important issue in preparing these particles is controlling their size and size distribution. A variety of factors can potentially influence these properties, which makes optimization of synthesis conditions somewhat demanding. Therefore, high-throughput (HTP) methods for developing new polymer particle synthesis strategies are of great value. Common synthesis challenges, such as isolation and purification of final products are not necessary to evaluate the size and size distribution of polymer particles, thereby simplifying HTP strategies. In this work, high-throughput non-aqueous dispersion (NAD) polymerization of poly(methyl methacrylate) (PMMA) and measurement of PMMA latex are performed using a new micro-semi batch reactor and/or microfluidic device integrated with online dynamic light scattering (DLS). The metallic microreactor was designed to handle the harsh conditions associated with NAD polymerization. On-line DLS was implemented for in situ monitoring of the PMMA latex particle size and size distribution. Polymeric surfactants consist of PMMA and poly(octadecyl methacrylate) (PODMA) with systematically varied composition, architecture, and molecular weights. These were synthesized under conventional batch condition by Cu-mediated atom transfer radical polymerization (ATRP). Comb polymers grafted with polyisoprene (PI) were designed and synthesized from backbone of a random MMA and glycidyl methacrylate copolymer. The properties of the surfactants were found to significantly affect the size and size distribution of the resulting particles. The dispersion polymerization of MMA using random copolymers as surfactants resulted in relatively large particles (~ 1 micron), whereas copolymers and comb polymer yielded nano-size particles (< 500 nm).