Raman Spectroscopy: Mutual Diffusion Coefficient in Hydrogels
A hydrogel kept at its equilibrium swelling state during taking the measurements controlled in a diffusion cell. The diffusion data gained from Raman spectra were analyzed to calculate the mutual diffusion coefficient in the hydrogel as semi-infinite medium. The relation between the solute concentration and Raman intensity for poly(N-isopropylacrylamide), which is characterized by the distinct peak for the isopropyl group at 2925 cm-1 was taken into account. The determination of the mutual diffusion coefficient, Dmut for hydrogels/phenol system was achieved successfully using confocal Raman spectroscopy at different solute concentrations. At 25oC, the value of the mutual diffusion coefficient is found between 5.61845x10-11 m2/s and 3.34565x10-9 m2/s for the hydrogel loaded with phenol of an initial concentration of 0.01 mM and 0.1 mM, respectively.
Andreas Öchsner, Graeme E. Murch and João M.P.Q. Delgado
A.A. Naddaf and H.J. Bart, "Raman Spectroscopy: Mutual Diffusion Coefficient in Hydrogels", Defect and Diffusion Forum, Vols. 312-315, pp. 193-198, 2011