Jk. Vrtis et Rj. Farris, MASS DIFFUSION-COEFFICIENTS OF POLYMER-FILMS USING REAL-TIME HOLOGRAPHIC-INTERFEROMETRY, Journal of applied polymer science, 59(12), 1996, pp. 1849-1855
The mass diffusion coefficient is obtained using real-time holographic
interferometry. The stresses induced during desorption and absorption
of moisture are monitored as a function of time at various relative h
umidities. A mathematical relationship is applied to relate these stre
sses to the moisture diffusion through the thickness of the films. The
advantage of the holographic interferometry technique is that both th
e swelling stress as a function of time and the mass diffusion coeffic
ient can be quantified simultaneously during the same experiment. Seve
ral films and coatings were investigated: polyimides (PMDA-ODA and BPD
A-PAA), photographic gelatin, and cellulose acetate. Each exhibited ch
aracteristic Fickian diffusion behavior. A gravimetric technique was e
mployed to validate the holographic interferometry results. The moistu
re diffusion coefficients determined by holographic interferometry agr
eed well with reported Literature values. (C) 1996 John Wiley & Sons,
Inc.