Structure and Solvent Properties of Microemulsions

Abstract

A microscale laboratory experiment to investigate the formation and utility of microemulsions is described. Microemulsions are technologically important fluids that can reduce the use of toxic organic solvents. In the experiment, students prepare a microemulsion and compare the solubility of sudan III dye in the microemulsion and in dodecane. They learn how to prepare standards, make absorbance measurements, plot calibration curves, and calculate the concentration of saturated solutions using Beer's law and dilution factor. Students also investigate the use of microemulsion to remove contaminants from soil using sudan III dye as a segregate model organic compound. This introduces the concept of waste remediation using a benign hydrophobic dye as a soil contaminant. In an optional part of the experiment, students can use fluorescence spectroscopy to probe the structure of micelles and microemulsions. The experiment is suitable for intermediate- and advanced-level students in environmental and analytical chemistry.