External factors and nanoparticles effect on water vapor permeability of pectin-based films

Permeation of water vapor through hydrophilic films is a rather complicated phenomenon. Water vapor permeability (WVP) of pectin films containing silicon dioxide nanoparticles was investigated under different temperature and relative humidity (RH) conditions, using orange and mango peel as pectin sources. No significant effect of the pectin source on WVP was observed. It was found that WVP increased with increasing RH and RH gradients created by different water vapor pressures in either sides of the films. Permeation tests showed that silicon dioxide nanoparticles in the films significantly reduced WVP (30-60%), compared to films without nanoparticles. Changes of WVP with temperature followed an Arrhenius type behavior and the activation energy of permeation decreased as RH increased. The opposite effect of temperature on diffusivity and solubility was observed.