Model-based product-process design of microgels
In the research area B, the mechanisms are identified, which govern the properties of microgels on the various length scales. The goal is to arrive at a quantitative understanding of microgel properties, and to establish the basis for the rational design of microgels tailored to a given application as well as of unique opera-tions and processes. It develops and builds on a broad range of mathematical models for all the phenome-na contributing to the product and process performance. These models have to span multiple scales ranging from the atomistic scale of individual ions and monomers to the macroscopic scale of a huge number of interacting microgels as they appear in process units or the production process as such. This is necessary to address and optimize both the functional properties of microgels and to guide the integrated design of continuous production processes and their control systems.
Research area B involves the micro-scale projects (B3 and B8) that aim at the prediction of the structural and dynamical properties of individual microgels, which are fundamental for production and appli-cation processes. They are complemented by the projects B4, B5 and B6, which address the behaviour of a microgel population in a macro-scale production process. The design and validation of (semi-)continuous pilot processes is envisioned.
Project B3 addresses the switching behaviour of complex microgels that is caused by the interaction with small molecules (co-nonsolvency effect) or with macromolecules (formation of polyelectrolyte complexes). It will focus on the kinetics of swelling transitions and combines theoretical models with experiments.
The focus of B4 is set on merging the results of experimental analysis and the mathematical modeling quantitatively in order to obtain a predictive model. Methods for model identification, parameter estimation and model-based optimal experimental design will be adapted and applied using both the macro-scale and the multiscale approach. Building on results of B1, quantum mechanical ab initio modeling of rate coefficients will be added as an additional means to overcome some of the model identification challenges. Microgels with increasingly complex morphologies and functions will be synthesized. The influence of process parameters will be examined as steps towards model-based process design of the synthesis of functional microgels.
B5 aims to develop continuous production processes to prepare uniform rod-shaped microgels with different aspect ratios (length/diameter). Two different new production processes will be engineered for semi-continuous and continuous production of rod-shaped microgels: semi-continuous electrospinning / microcutting and flow focusing microfluidics. After production, the structural organization of microgels at high volume fractions (nematic vs. isotropic) will be investigated in a confined volume. Such 3D assemblies could potentially be applied for microfluidic chromatography, microfluidic membrane filtration or tissue en-gineering applications.
B6 investigates membrane filtration processes for the concentration, purification and separation of ionic microgels: in particular, it focuses on the interaction of hydrodynamic conditions, membrane porosity and colloidal interactions. It addresses cross-flow ultrafiltration, cross-flow microfiltration and membrane fouling effects.
The new project B8 studies the influence of microgel architecture and chemical composition on their be-havior at fluid interfaces. Branched and cross-linked macromolecules will be synthesized to achieve a systematic transition from molecules to particles whereby the latter are distinguished by their defined shape and surface. This project is based on results obtained during the first funding period of the SFB in other projects, mainly A3 and C1. The interfacial properties will be probed various experimental techniques as well as by computer simulations.