Porous Materials Research Areas
Biomedical Project Examples
Characterizing porous materials
The Allgeier lab uses a technique known as low-field nuclear magnetic resonance (LF-NMR) to study hydrogels. Hydrogels are employed in a number of biomedical applications from contact lenses to drug delivery and wound care. The performance of hydrogels is dependent upon their porosity, e.g. in drug delivery reduced pore sizes can restrict the rate of drug diffusion into the body. Students would learn how to use various instruments, including the LF-NMR to detect differences in hydrogel porosity and X-ray micro-computed tomography (XµCT).
Nano- and microfibers for tunable drug delivery and tissue engineering
Postmenopausal women experience osteoarthritis (OA) at a higher rate than age-matched men suggesting estrogen deficiency may play a role in the pathogenesis. Hormone replacement therapy with estrogen delivered systemically is the current standard of care but often increases the risk for breast cancer. Thus, targeted release of an estrogen receptor (ER) agonist is hypothesized to promote anabolic effects and reduce detrimental side effects. To address this hypothesis, Dr. Robinson’s group seeks to develop porous fibrous meshes that mimic the fiber structure of native extracellular matrix. By engineering these materials to controllably release ER agonists, they will promote regeneration and provide relief to patients with OA. Students may use electrospinning emulsion solutions to create fibrous meshes, and then assess fiber morphology, alignment, and pore architecture. Further, students could determine the release kinetics of a model protein as a function of pore size and interconnectivity.
Stabilizing vaccines with porous materials
Vaccines degrade at elevated temperatures because the proteins in the vaccine unfold and lose their functional structure. Vaccine storage and distribution therefore relies on a “cold chain” of continuous refrigeration which is costly and not always effective. Dr. Shiflett’s group is developing new techniques to deposit vaccines in the pores of mesoporous silica in order to stabilize the protein from the effects of elevated temperature. The REU students working on this project would learn about vaccines and mesoporous silica materials with pore sizes capable of capturing and storing proteins. Students would learn how to characterize the silicas’ surface area, pore size and volume using a Micrometrics ASAP instrument, and how to deposit proteins in silicas using wet impregnation methods. The students would be taught how to measure the amount of protein deposited by measuring the difference in solution using a NanoDrop 2000 UV-vis and how to characterize the secondary protein structure using circular dichroism. They may also learn how to invent new products and how to write patents.
Probing the interaction and potential toxicity of porous materials
Projects include the study on the impact of soft vs. hard porous materials on biological systems, particularly cell membranes, in an effort to access the cytotoxicity of these novel materials. They utilize biophysical and analytical techniques unique to the Dhar and Allgeier labs in order to measure changes in model membrane structures when they interact with porous materials. This includes an opportunity to learn about and personally utilize advanced scientific instrumentation including biophysical tools such as a Langmuir trough, custom designed to be coupled with fluorescence microscopy and a low-field NMR to characterize porous material interactions with biomolecules. Students may learn to interpret data elucidating the basics of biomolecule/porous particle interactions, the significance of health impacts of our studies, and fundamentals of both biomedical and chemical engineering fields where concepts learned in their coursework will be applied in a research setting (e.g. thermodynamics, fluid mechanics).
Catalysis Project Examples
Porous materials for the electrocatalytic conversion of H₂O into H₂ and O₂
Splitting water into hydrogen and oxygen by electrocatalysis plays a vital role in converting solar energy into chemical energy, and it provides a pathway to use water (as opposed to natural gas) as a feedstock for hydrogen production. Dr. Leonard’s group recently developed a new way to synthesize porous nanoamorphous oxide structures. Students may prepare electrocatalysts using Dr. Leonard’s novel method. They would gain hands-on experience with cyclic voltammetry, gas chromatography, and electron microscopy (SEM and TEM) instruments, learning to interpret data and consider economic/sustainability impacts for commercial viability of new innovations.
Mesoporous solid acid catalysts for alkylation and dehydration reactions
Solid acids are used as catalysts for a wide range of industrial chemical processes, such as the alkylation of isobutene with olefins to generate high octane blending stocks for premium gasoline. A mesoporous material, with a pore diameter of 2-50 nm, is needed to facilitate diffusion and conversion of bulkier substrates and products. Dr. Subramaniam’s group has synthesized new solid acid catalysts by incorporating metals into ordered mesoporous silicas. The REU students may have the chance to explore various applications for these materials, such as the alkylation of 1-butene and isobutane (shale gas derived reactants) to isooctane (a gasoline additive) and the dehydration of biomass-derived glycerol to acrolein (a polymer precursor). Students might learn how to synthesize and evaluate these catalytic materials using GC/FID and HPLC techniques, thermogravimetric analysis, and N2 physisorption. Dr. Subramaniam has expertise in conducting economic and life cycle assessments, and students would learn how understanding such data is critical for effective research and business decision-making.
Catalysts for gas adsorption and reaction
Producing fuels and chemicals depends on porous solid catalysts to facilitate reactions. A common reaction for catalysts is dehydrating alcohols to olefins. This is the key step to making polyethylene from bio-renewable resources for plastics and synthetic fibers. Dr. Bravo-Suárez’s group seeks to synthesize and test various combinations of mixed metal oxides (MMO) as catalysts for this reaction. His group modifies the porosity and surface composition of catalysts and uses advanced analytical techniques for characterization. Students would learn about catalyst structure using principles of solid-state inorganic chemistry and will also gain experience with cutting-edge analytical methodologies. They may also learn how to use Dr. Bravo-Suárez’s specialized equipment including ultraviolet-visible, Fourier transform infrared, and Raman spectrometers.
Supported Ionic Liquid Phase (SILP) Catalysis
Hazardous acidic or basic catalysts in industrial scale processes need safer alternatives. A new system called Supported Ionic Liquid Phase (SILP) catalysis has been proposed as an alternative to hazardous acids. While SILPs have been applied to a number of different reactions, Dr. Scurto’s group uses a liquid mixture of a non-volatile and molecularly-tunable ionic liquid and soluble catalyst to coat a solid support at the micro-/meso- scale. The IL phase sequesters and influences the reaction and separation for many potential catalysts, while the solid support provides large surface area for increased mass transfer over traditional gas-liquid or liquid-liquid processes. This also reduces the amount of ionic liquid used in the process, improving the economics. Students would learn how to synthesize SILPs with different ionic liquids to explore gas phase C4 alkylation. They may also learn how to characterize the catalysts with specialized equipment, such as a tapered element oscillating microbalance (TEOM).