(247h) A Simple Optical Experiment On Polymer Diffusion for Undergraduates That Incorporates Web-Cam Capture, Data Digitization, and Multi-Variable Regression

Diffusion is studied due to its fundamental importance in various fields of biomedicine, chemical technology and nanotechnology. Measuring diffusivity of polymers is necessary in the development and design of different processes involving polymer diffusion. A laboratory experiment to emphasize concepts of macromolecular diffusion for undergraduate students can, therefore, be valuable. Sophisticated equipment that have evolved in the past for measuring diffusivity are not suitable for undergraduate instructional laboratories because of cost, complexity and difficulty in demonstrating diffusion concepts in a straightforward manner. A simple, cost effective and visually instructive optical method to measure polymer diffusion coefficients will be presented that is based on Weiner's method. Refraction of laser light is employed to analyze the relationship of size, shape and solution environment on diffusion coefficients of common linear and globular polymers such as poly(ethylene glycol), poly(vinyl alcohol), chitosan and bovine serum albumin. We have also added features such as digital capture of data using a webcam, data digitization, and multi variable regression that provides opportunities for students to learn tools that can be valuable in their academic and professional career.