AOT in isooctane Reverse Micelles Varying Size and Phase Stability with Amides: Comparison of Urea Formamide and Acetamide

Authors

Josh Heitert, DePauw University
Bridget Gourley, DePauw University
Nancy Levinger, University of Colorado, Denver
Yayo Virgen

Files

Document Type

Poster

Publication Date

10-1-2025

Abstract

Acetamide, Formamide, and Urea are all polar, highly water-soluble molecules; this makes them useful as osmolytes in model systems for nanoconfinement. These model systems form from Aresol-OT (AOT) in isooctane reverse micelles with the osmolyte present at the interface, forming an AOT/isooctane/polar phase system. The systems are characterized by their Wo,which is a measurement that can impact the size of the reverse micelles and is defined as Wo = [Polar phase]/[Surfactant]. Here, we measure the impact of these various osmolytes on the size of the reverse micelles at different concentrations and at different Wo using dynamic light scattering (DLS). The size of the reverse micelles, as quantified by hydrodynamic diameter using DLS, follows an observable trend, with size increasing following the addition of osmolytes. Additionally, by adding a high concentration of these osmolytes, we see the partitioning of the sample into multiple reverse micelle groups. Along with measuring size using the DLS, we measured phase stability by creating ternary phase diagrams based on the formation of reverse micelles at various concentrations and Wo. This data shows an observable trend regarding the stability levels of each osmolyte’s system; systems with formamide are the most stable, followed by those with acetamide, and then those with urea. Furthermore, the diagrams show that the addition of any of the three osmolytes shrinks the single-phase microemulsion, indicating that stability is reduced as a result of the osmolytes having a destabilizing impact.

Department

Department of Chemistry, Depauw University, Greencastle IN and Department of Chemistry, Colorado State University, Fort Collins, CO

Project Mentor

Dr. Gourley and Dr. Levinger

Funding and Acknowledgements

Dr. Gourley and Dr. Levinger's NSF grant

Recommended Citation

Heitert, Josh; Gourley, Bridget; Levinger, Nancy; and Virgen, Yayo, "AOT in isooctane Reverse Micelles Varying Size and Phase Stability with Amides: Comparison of Urea Formamide and Acetamide" (2025). Annual Student Research Poster Session. 209.
https://scholarship.depauw.edu/srfposters/209