Factors governing water absorption by composite matrices

The water transport mechanisms in organic matrices were reconsidered in two ways. Attention is focused on solubility rather than concentration in the analysis of equilibrium properties and a model in which polymer/water interactions govern, at least partially, diffusion is proposed. This model allows us to explain a certain number of experimental results, for instance: the fact that the number of sorbed water molecules is lower than the number of polar groups and that it increases pseudo parabolically with this latter; and the facts that diffusivity is globally a decreasing function of hydrophilicity; that its apparent activation energy is generally close to that for solubility, and that it tends to vary in the same sense with structure.