Dynamic Optimization of a Fed-Batch Microgel Synthesis

Abstract Functional microgels are novel materials, which can potentially be used for diverse applications such as drug delivery. Among other material properties, the radial cross-linker profile is of special importance to ensure desired product functionality. However, in the system under investigation, only a high cross-linker fraction in the center and a low cross-linker fraction in the shell is obtained in batch synthesis due to the fast reaction kinetics of the cross-linker. Other radial cross-linker fraction profiles can be synthesized in fed-batch, yet the determination of the required feeding profiles is not intuitively obvious. Based on recently developed quantitative nonlinear process models, a fed-batch synthesis can be dynamically optimized under constraints set by product quality and process limitations. Here, we apply dynamic optimization to microgel synthesis to obtain large microgels under constraints posed by the radial cross-linker profile and conversion. We present three different case studies to show in silico that a wide range of different cross-linker fraction profiles is feasible. The results show that the specified constraints are met and that various cross-linker profiles can be achieved while maintaining the microgel size.