Salt-induced diffusiophoresis is the movement of a charged nanoparticle in water, driven by an imposed directional gradient of salt concentration. This transport phenomenon has become a valuable tool for manipulating charged nanoparticles within porous materials and microfluidic systems. Micelles are a typical example of nanoparticles with the important ability to host small guest molecules. Therefore, micelle diffusiophoresis is also crucial for manipulating small molecules. This poster reports measurements of diffusiophoresis coefficients carried out on aqueous mixtures of the surfactant, hexadecylpyridinium chloride (CPC) in the presence of NaCl by Rayleigh interferometry. Measurements of NaCl osmotic diffusion from high to low micelle concentration are also reported. We observe that diffusiophoresis of CPC cationic micelles occurs from high to low salt concentration. A model describing the behavior of micelle diffusiophoresis as a function of NaCl concentration is reported. Our diffusiophoresis results are explained in terms of micelle electrical charge, salt osmotic diffusion coefficients and zeta potential. This work offers new insights into diffusiophoresis of charged nanoparticles with potential applications for enhanced-oil recovery from porous rocks, soil remediation and diffusion-based mixing inside microfluidics.

The development of cerium oxide (CeO2) nanomaterials is rapidly advancing, driven by their wide range of applications in catalytic converters, solid oxide fuel cells, and biological sensors. Considering this, doping CeO2 with rare earth elements such as Europium (Eu3+) not only enhances its catalytic properties but also adds visible fluorescence to the list. To explore the variability of this effect, Eu3+ doped CeO2 nanotubes were synthesized and carefully analyzed by varying the Eu3+ concentration to investigate their optical properties, crystallinity, and morphology. Current research is focused on evaluating the potential of these doped CeO2 nanotubes as probes for bioimaging and optical sensors.

Reactive oxygen species (ROS) are byproducts of normal cellular metabolism. While essential in cell signaling and immune responses, unregulated or chronic levels of elevated ROS can cause oxidative stress. If this occurs in the brain, oxidative stress can lead to irreversible damage of macromolecular structures, including neuronal cell damage. Excessive ROS species are a hallmark of Alzheimer’s Disease (AD) and other neurodegenerative disorders. Superoxide dismutase (SOD) enzymes serve as a critical defense mechanism against ROS but have been found in lower concentrations in individuals with neurodegenerative disease. As a result, water-soluble small molecules that can mimic the SOD1 activity are of great interest to controlling diseases derived from oxidative stress. Herein, we present the SOD mimic activity for a library of copper tetra-aza macrocyclic small molecules and compare it to the most active congeners reported to date.

Texas is home to significant mining activity, both for oil and gas but also for other industrially useful materials. One such material is calcium carbonate. The chemical instrumentation course was contacted by a local mining company interested in analysis of soil samples from potential drilling locations, specifically determining calcium content and the presence of hydrocarbons. Over the course of the semester, the students in chemical instrumentation have analyzed four separate soil samples for both calcium content and various hydrocarbons using multiple instruments in the chemistry department including atomic absorption spectroscopy, infrared sprectroscopy, GCMS, thermogravimetric analysis, and NMR. We determined that calcium is present in the soil samples in concentrations up to 5% by mass, and that some hydrocarbons are present.

Photoelectrochemical (PEC) systems can be used to harness solar energy to drive sustainable oxidations reactions, such as those mediated by TEMPO ( 2,2,6,6-tetrameth-ylpiperidinyl-N-oxyl), a stable radical with applications in organic synthesis. This work focuses on preparing bismuth vanadate (BiVO4) films for multilayer electrodes (FTO|WO3-BiVO4-NiO) to enable PEC TEMPO oxidation studies. Double-layered BiVO4 films were fabricated on fluorine-doped tin oxide (FTO) substrates through dip-coating and a subsequent thermal treatment at 450°C. Various means of optimizing film performance and quality were explored, including precursor stoichiometry, dipping frequency, and drying conditions.

Our experiments demonstrate that the uniformity and quality of BiVO4 firms are greatly dependent on preparation parameters. Adjustments to the drying procedure, designed to slow solvent evaporation, resulted in improved uniformity as observed through UV-Vis spectroscopy and profilometry. Photoelectrochemical testing of select replicates under illumination confirmed photoactivity, with distinct differences between dark and light conditions. Further experimentation with cyclic voltammetry and chronoamperometry will explore the efficiency of these films in greater detail. This work establishes an effective approach for BiVO4 film preparation for future use in WO3-BiVO4-NiO multilayer electrodes for TEMPO oxidations studies and advancing solar-driven oxidation processes.