PNNL

Abstract

This two-session undergraduate laboratory experiment in physical chemistry involves the measurement of the viscosity of solutions using both a conventional method and a new method based on the fluorescence depolarization of a probe molecule. By comparing the results of the two approaches, students will come to a fundamental understanding of how a macroscopic property (viscosity) and molecular-level properties (molecular dynamics parameters) relate. They will also further their understandnig of the physical chemistry of fluorescence and learn how to perform spectroscopic measurements where polarization conditions are important. The experiment also has ramifications in the practical world, because the optical approach has shown promise as the basis for a sensor for in-situ viscostiy measurement.