Dissertation
Screening for tunable properties of ionic liquids using two-dimensional infrared spectroscopy and atomic force microscopy
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2023
DOI: 10.25820/etd.006906
Abstract
liquids (ILs) a class of salts that are liquid at room-temperature, have potential applications in batteries, lubrication, CO₂ capture, and separation processes. With thousands of ionic liquids in existence, there is a pressing need for effective methods to characterize them. This thesis encompasses the development and integration of a high-throughput rapid data acquisition method for two-dimensional infrared (2D IR) spectroscopy, the design and implementation of a novel optical parametric amplifier to enhance mid-infrared power, and utilization of tapping-mode atomic force microscopy (AFM) for the acquisition and analysis of phase images of ionic liquids confined within nanowells. The utilization of high-throughput 2D IR spectroscopy provides valuable insights into the spectral and rotational dynamics, intermolecular interactions, and molecular structure of these liquids. By employing automated sampling and model fitting techniques, this approach allows for swift characterization of IL samples. To address the demand for enhanced mid-IR power in 2D IR spectroscopy applications, this thesis examines a cost-effective and easily implementable approach that involves incorporating an additional amplification stage that utilizes discarded light as the pump source, resulting in a two-fold improvement in mid-IR power. Additionally, this thesis explores the application of phase imaging atomic force microscopy to measure the tunable mechanical properties of ionic liquids confined in nanowells. The obtained results demonstrate a clear correlation between the size of nanoconfinement and the stiffness of the ionic liquid.
Details
- Title: Subtitle
- Screening for tunable properties of ionic liquids using two-dimensional infrared spectroscopy and atomic force microscopy
- Creators
- Whitney Harmon
- Contributors
- Christopher M Cheatum (Advisor)Scott K Shaw (Advisor)Renée S Cole (Committee Member)Claudio J Margulis (Committee Member)Aditi Bhattacherjee (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Chemistry
- Date degree season
- Summer 2023
- DOI
- 10.25820/etd.006906
- Publisher
- University of Iowa
- Number of pages
- ix, 58 pages
- Copyright
- Copyright 2023 Whitney Harmon
- Language
- English
- Date submitted
- 07/25/2023
- Description illustrations
- illustrations (some color)
- Description bibliographic
- Includes bibliographical references (pages 49-58).
- Public Abstract (ETD)
This thesis explores ionic liquids (ILs), a type of liquid salt with exciting applications in batteries, lubrication, and environmental processes. With thousands of different ionic liquids known and billions more possible, it is crucial to find efficient ways to study and understand them.
Using two-dimensional infrared spectroscopy (2D IR), we can study the movement (flipping, moving, bumping) of ionic liquids on the timescale on which these motions occur, which is essential to develop a fundamental understanding of ILs. This method requires the use of laser pulses to observe these motions. However, generating enough laser power for this technique is an ongoing challenge in the field. This thesis addresses this problem by introducing a novel optical design that doubles power.
Furthermore, the thesis presents an automated approach for the rapid characterization of various ionic liquid samples using 2D IR spectroscopy and showcases the first example of its successful implementation. By streamlining the process through automation, valuable insights can be gained to identify suitable candidates for future applications.
Lastly, ionic liquids have strange behavior when confined within square wells, with dimensions less than a millionth of a meter. This thesis explores the properties of ionic liquids and how those properties change in confined spaces. This research advances the knowledge and potential applications of ionic liquids in various fields.
- Academic Unit
- Chemistry
- Record Identifier
- 9984454642102771
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