Polymer, Vol.41, No.20, 7531-7538, 2000
Packing effect on oxygen diffusion in latex films; a photon transmission and fluorescence study
Photon transmission (PT) and steady state fluorescence (SSF) methods were used to study latex film formation and oxygen diffusion processes, respectively. Films with different latex content were prepared separately by annealing pyrene (P) labeled poly(methyl methacrylate) (PMMA) particles above the glass transition temperature. Annealing was performed at three different temperatures. The transmitted photon intensity from these films decreased as the latex content is increased. It is observed that as the latex particles are packed more voids or cracks are formed in the films. Absorption coefficients, kappa, were measured for each film sample annealed at different temperatures. The SSF method was employed to monitor oxygen diffusion into these latex films. Diffusion coefficients, D, of oxygen were determined for various films of different thicknesses and at different annealing temperatures and were found to increase from 0.45 x 10(-10) to 73 x 10(-10) cm(2) s(-1) by increasing the film thickness from 10 to 100 mu m. No temperature effect was observed on the diffusion coefficient, D, values.