Note: Visit the "Group Meeting" tab for in-depth information on the theoretical concepts and applications of many of these techniques.
Vibrational Spectroscopy: Infrared | Raman | Sum Frequency Generation
Spectroscopic Ellipsometry | Contact Angle Goniometry | Electrochemistry
Quartz Crystal Microbalance | LV Viscometer | Gas Chromatography | Glovebox
This instrument is a workhorse of the group, providing high resolution infrared spectra of our chemical systems via several acquisition geometries. The polarization modulated technique is particularly useful in detecting ultra-thin films (ca. 1 to 1000 nm) and providing molecular level details on structure and orientation.
- Spectra Physics 532 nm, 300 mW Excelsior laser
- J.Y. Horiba iHR320 imagine spectrometer
- Andor Newton CCD Detector
Our Raman spectroscopy system is a custom build, with the best components selected from multiple specialized vendors. It is designed for maximum flexability and can acquire Raman scattered photons from bulk samples, thin film coatings, environmental substrates, or bulky 'real-world' objects.
The vSFG system features a picosecond, diode-pumped laser at 1064 nm fundamental and an optical parametric generator to create tunable (2.3 to 10 µm) infrared light. The optical layout allows selection of polarization angles for all incident and collected beams, as well as direct conversion between vSFG and SHG measurements. A custom sample stage allows collection from samples in both vertical and horizontal sample planes, supporting dynamic wetting and vapor/liquid interface studies.
This research grade ellipsometer from J.A. Wollam is specially designed to accommodate the vertical sample position required for some work done in our lab. It is a key technique we use to confirm the thickness of films or oxide layers on our substrates, as well as to measure refractive index and other optical contacts of the materials we use in all of our active research areas.
The Thorlabs research grade scientific camera combines with the Eppendorf electronic dispensing system to create a system capable of capturing high resolution images of liquids coming into contact with a surface, providing a characterization of the wettability of a surface via contact angle measurement.
We have two instruments from CHI: these are a 660-D electrochemical analyzer and an 1100-B electrochemical workstation. Both of these systems are used to characterize, and sometimes to create, the chemical system in our research. The 660-D is truly an all-in-one potentiostat with extensive capabilities from standard cyclic voltammetry all the way to impedance vs. potential scanning. The 1100-B is used for screening analysis and to provide electrochemical control for experiments that combine spectroscopy with a defined current or applied electrochemical voltage. For a full list of their capabilities, please click on the following links:
This SRS quartz crystal microbalance (QCM) measures mass and viscosity of fluids or gels that exist near surfaces and within thin films. The instrument reads the resonant frequency of a quartz crystal, which changes as a linear function of the mass of material deposited on the crystal surface (via the Sauerbrey equation). This QCM can resolve mass changes at the sub-nanogram level, enabling analysis of (sub)monolayer films. Additional applications include observations of phase transitions, swelling, and cross-linking. A flow cell attachment enables liquid and gas phase analyses to probe a variety of chemical systems.
Our viscometer is fitted with an LV internal spring capable of measuring low viscosity materials and thin fluid films (range: 1 cP to 6M cP). This allows us to characterize the dynamics of ionic liquids and other fluids (see Research tab) under controlled temperatures and tie the rheological properties to other parameters of interest, such as film thickness and capacitance.
Our GC can be used to reliably separate and analyze compounds that can be vaporized without decomposition. The instrument is equipped with a thermal conductivity detector (TCD) which is a ‘universal’ detector that can respond to all compounds excluding the carrier gas. Fitted with either a Mol Sieve 5A PLOT or Carboxen PLOT capillary GC column, we can separate and quantify hydrogen, carbon monoxide, carbon dioxide, methane and most C1 and C2 light hydrocarbon molecules. That makes this instrument an invaluable tool to detect and analyze products from our carbon dioxide reduction in ionic liquids projects. Given the very low detection limit of 5 ppm for most analytes the HP 5890 GC is used for both headspace and bulk solution analysis of volatile compounds.
Our glovebox provides an inert nitrogen atmosphere using independent purifiers to control oxygen and water at the ppm level, facilitating experiments that would otherwise be very sensitive to oxidation and ambient moisture.
Our group utilizes several tools made available by instrumentation facilities and other research groups at the University of Iowa. Instruments key to our research are listed below.
Asylum Research MFP-3D Atomic Force Microscope (Dept. of Chemistry, University of Iowa)
This instrument provides nanometer resolution topography images of our substrates and films.
Angstrom Engineering Amod Electron Beam Evaporator (Microfabrication Facility - Optical Science and Technology Center, University of Iowa)
This OSTC instrument, housed in the Iowa Advanced Technology Laboratory of the University of Iowa, is a versatile thin film deposition tool. We utilize this instrument to prepare substrates for a variety of research applications.
Smooth, reflective substrates can be prepared by thermally depositing a film of reflective metal on glass.