Laser-induced fluorescence lifetime spectroscopy to determine oxygen solubility in polymeric layered composite films

CHED 713

Lukas T. Kromer, l-kromer@onu.edu, Kevin A. Craigo, k-craigo@onu.edu, Nicholas J. Dunn, Ryan L. Wheaton, and Jeffrey A. Gray, j-gray@onu.edu. Department of Chemistry, Ohio Northern University, 525 S. Main St., Ada, OH 45810
Advanced polymeric materials are finding novel applications that require control of the permeability to oxygen gas. We are developing an optical method for determining oxygen transport through layered composite polymer films. The sensor material, tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II), a.k.a. Ru(dpp)32+, is dissolved into films and excited using a pulsed laser operating at blue or UV wavelengths. Red fluorescence from Ru(dpp)32+ is resolved on the microsecond time scale and the fitted decay rate is a multi-exponential function of quenching by oxygen, which may be inhomogeneously distributed in layers or interfaces between different materials such as polystyrene or polymethylmethacrylate. The resulting distribution of decay rates form a spectrum displaying peaks that shift and broaden to indicate how oxygen diffuses through the film. Fluorescence-based sensors may enable rapid testing of oxygen dissolved within micro-layered polymers being developed for advanced packaging and electronics applications.
 

Undergraduate Research Poster Session: Polymer Chemistry
11:00 AM-1:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster

Division of Chemical Education

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008