Integrated Microfluidics for Targeted Applications Including Polymerization, Carbon Dioxide Sequestration and Gas Separation

The work presented in this thesis explores the utilization of microfluidic (MF) reactors fabricated in different materials for targeted applications and capitalizes on various fundamental advantages inherent to MFs for studying chemical reactions. In Chapter 3, we describe MF reactor fabrication in polymer materials, including polycarbonate, cyclic olefin polymer, acrylic polymer, polyethylene, poly(vinyl chloride), and polystyrene to address the previous lack of MF reactor materials that are chemically stable in polar and nonpolar solvents, have gas impermeability, are cost-efficient, and biocompatible. We investigated polymer performance under specific conditions and optimized fabrication conditions of MF reactors following well-defined requirements. Chapter 4 explores development and utilization of a MF platform with integrated online attenuated total reflection Fourier infrared spectroscopic characterization for studying kinetics of an exemplary reaction, namely, polymerization of N-isopropyl acrylamide in the presence of accelerator N’,N’,N,N–tetramethylethylenediamine, and initiator ammonium persulfate. The polymerization was studied in flow in a high-throughput manner at various reagent concentrations and pH values. Monitoring the rate of disappearance of the monomer IR band vs. time, we obtained reaction orders with respect to reagents and found good correlation to values reported in the literature. In Chapter 5, we utilized MF reactors by generating segmented flow of CO2 gas and solvent (bromobenzene) to investigate fundamental information, such as thermodynamics and reaction efficiency, of the reaction involving CO2 gas and Frustrated Lewis pairs (FLPs). We developed a method to overcome the challenges inherent in batch processes and successfully obtained ΔG, ΔH, ΔS, and enhancement factors, in the temperature range from 0 °C to 40 °C. This information is vital for future optimization and development of FLPs. Finally, Chapter 6 explores the use of FLPs to effectively separate gases by extracting one gas in a reactive solvent phase. We used MFs to assess the efficiency of the separation of ethylene from its mixture with ethane, due to the chemical reaction of ethylene with FLP. Increasing the FLP concentration and reducing the temperature from 25 to 0 °C, led to significant increase separation of ethylene. The resultant separation factor for ethylene was 7.3 with an ethylene purity of 88%.Ph.D