Where Q_ is the mole of water uptake at equilibrium, Qt is the mole of water uptake at time t, and k and n are constants.The constant k indicates the interaction between polymer and water, and n is the diffusion exponent,which tells about the mode of diffusion. The values ofn and k were calculated with the help of linear regression method. When n _ 1⁄2, diffusion obeys the Fick’slaw; this occurs when the segmental mobility of the polymeric chains is faster than the rate of diffusion ofwater molecules. When n _ 1, the mechanism is non-Fickian; this occurs when water diffusion rates are much faster than segmental mobility of the polymericchains.