ABSTRACT:

Advanced x-ray and neutron scattering techniques are powerful tools for 
elucidating nanoscale structure and dynamics in a variety of science 
challenges. This talk will present research examples from supercapacitor 
materials, proteins, and asphaltenes, where interfaces play a crucial 
role in determining a system’s behavior. To develop novel electrical 
energy storage devices, such as supercapacitors, the properties of 
electrolyte molecules at the fluid-solid electrode interface where 
energy is stored, must be understood. Room-temperature ionic liquids 
(RTILs) have emerged as promising electrolyte materials due to their 
extremely low vapor pressure and high thermal and electrochemical 
stability. The highly porous, high surface area electrodes, however, 
introduce confinement and surface effects on the properties of RTILs. 
Structural studies of RTILs in the bulk state, in mixtures, under 
nano-confinement, and efforts to measure electric potential-dependent 
properties and integrate them with molecular modeling approaches will be 
discussed. Another goal of our lab is to understand the factors which 
bring thermal stability to biomolecules which is relevant in areas such 
as medicine and bio catalysis. We are currently investigating the 
effects of ions, deep eutectic solvents, and ionic liquids on a 
protein’s structure and stability. Recent small-angle x-ray scattering 
and light spectroscopy results investigating temperature stability of 
several globular proteins, namely lysozyme, myoglobin, and human serum 
albumin in different environments will be discussed. Finally, 
asphaltenes are a group of planar molecules found in crude oil and are 
prone to aggregation which causes blockage at the source rock or in 
pipes along the oil production stream. We have characterized the 
concentration and solvent-dependent fractal aggregate structure of 
asphaltenes using analytical models whose parameters may be linked to 
theoretical models of aggregation. Small-angle scattering is ideal for 
addressing systems which exhibit heterogeneity in structure, whether it 
is due to density fluctuations in liquids or aggregation of 
nanoparticles, and is fertile ground for collaboration with theorists 
interested in such phenomena.