Photoinitiated miniemulsion polymerization in microfluidic chips on automated liquid handling stations: Proof of concept

Abstract

Photoinitiated polymerization is usually applied in the area of specialty chemicals and UV curing but can also be employed in the production of biofunctional polymers and nanocapsules. A promising approach for the preparation of those polymers is the photoinitiated polymerization of miniemulsions. Here, the mild reaction conditions are beneficial for the integration of sensitive biomaterials into the process. The optimal combination of different varied cause variables like irradiance, irradiation time, and height of the irradiated volume is crucial for an appropriate polymerization result. For the presented proof of concept study, a microfluidic tool was established to screen these cause variables in an automated high throughput manner on a liquid handling station (LHS). The experiments are planned and executed by means of a design of experiments (DoE) approach to investigate the effect of the variables on the residual monomer content (RMC) within the stated design space. As the RMC is considered as crucial for bioapplications, the optimal parameter combinations for the complete monomer conversion have been determined. The model‐based evaluation of the executed experiments resulted a channel height respectively optical path of 200–400 μm, an irradiance of 65% (equals 44.2 mW/cm²) and an irradiation time of 30 s for complete styrene conversion.