Mathematical Modeling of Vapor Sorption in Pyrene-Labelled Polystyrene LB Thin Film Studied by Surface Plasmon Resonance Spectroscopy

Sorption process by surface plasmon resonance (SPR) was studied by exposing polymeric film coated with pyrene-labeled polystyrene (PS) chains to various concentrations of saturated chloroform vapor. It was observed that the reflectivity changes were fast and reversible. The changes in reflectivity implied the swelling behavior of polymeric film during adsorbtion and can be explained by capturing of chloroform molecules. Fick's law for diffusion was used to quantify real time SPR data for the swelling proces. It was observed that diffusion coefficients (D_{s}) for swelling obeyed the t1/2 law and found to be correlated with the amount of chloroform content in the cell.