Fit of the release data to ktn (a) and Fit of the release data to φo(1 - exp(-kbt)) (b). The observed values and the fitted values to ktn when the pH values of the buffer solution are 4.0, 6.5, and 7.4. The values of the k and n are (67.215 h-1,0.25) for pH 4.0, (35.031 h-1, 0.40) for pH 6.5 and (22.184 h-1, 0.30) for pH 7.4, respectively. For the observed values and the fitted values to φo(1 - exp(-kbt)) of the φo and kb, which lead to the best fits are (100.00, 0.805 h-1), (70.430, 0.659 h-1) and (35.417, 0.605 h-1), respectively, for the three pH values of 4.0, 6.5, and 7.4.
Tang et al. Nanoscale Res Lett 2011 6:19 doi:10.1007/s11671-010-9761-4