ABSTRACT
The mechanism for water vapor permeation through hydrophilic films is extremely complex. The complexity is due to nonlinear water sorption isotherms and water content dependent diffusivities (Schwartzberg, 1986). Hydrophilic films are usually used in applications where water vapor migration is not detrimental or water solubility is advantageous (Donhowe and Fennema, 1994). The water vapor transmission of hydrophilic films varies nonlinearly with the water vapor partial pressure gradient. Since chitosan films are cationic and strongly hydrophilic, water interacts with the polymer matrix and increases permeation for water vapor (Pascat, 1986).
