UV-Free Microfluidic Particle Fabrication at Low Temperature Using ARGET-ATRP as the Initiator System

A new way to fabricate monodisperse polymer particles in a microfluidic device without UV-light and without the need for high temperatures is described in this article. By applying an activator regeneration by electron transfer - atom transfer radical polymerization (ARGET-ATRP) initiator system in a co-capillary microfluidic setup and by separating the monomer mixture in an initiator and a catalyst phase, a fast polymerization of the droplets at low temperature without premature curing and thus clogging of the capillaries can be achieved. The influence of the flow rates on the particle sizes and their polydispersity as well as the controlled character of the polymerization are investigated. The particle size is well adjustable, but the reaction is not controlled due to the high radical concentration needed for rapid polymerization. In addition, particles with incorporated UV-dyes are produced as a proof of concept at low temperature.