Investigation of the formation mechanism of homo- and copolymer microgels for a model-based process design of microgels
Ksiazkiewicz, Agnieszka Natalia; Pich, Andrij (Thesis advisor); Richtering, Walter (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, RWTH Aachen University, 2020
Process analytical technology (PAT) is used widely in pharmaceutical and biotechnology industries to monitor and control the parameters of the processes during product manufacturing. For these sectors, PAT is a crucial department to maintain the quality of the product. It can be implemented in-line, where the sample is not removed from the process stream. However, PAT can also be used to monitor and control the reaction progress in order to learn more about the product formation mechanisms. In this work, PAT will be applied to synthesis of microgels – cross-linked polymeric networks that can respond to diverse stimuli. It will be shown how the in line analytical techniques can improve the understanding of microgel synthesis processes. The in-line monitoring techniques focus on reaction calorimetry, turbidity, dynamic light scattering (DLS) measurements and Raman spectroscopy. Moreover, it will be discussed how computational simulation can benefit and support the experimental studies on microgels. Collaborative approach combining experimental findings and simulated predictions can help to generate microgels of different sizes, shapes or properties and study their reaction mechanisms. The study will focus on temperature responsive microgels based on N vinylcaprolactam (VCL) and N-isopropylacrylamide (NIPAM) monomers or their copolymers. The microgel synthesis will focus on batch and semi-batch methods as well as studies on how nitrogen purging approach prior to polymerization initiation influences the microgel formation process and the final product. In-depth study will be discussed on enlarging the microgel diameters as well as generating different shapes of microgels functionalized with hydrophobic polymers. The aim of this work is to undergo fundamental studies on well-known temperature responsive microgel systems in order to better understand their formation mechanisms. Furthermore, the motivation of the project is to gain the ability to predict more complex microgel systems for versatile applications and scale-up synthesis processes.