Water vapor permeability of an emulsion coating of maltodextrin and surfactants

Emulsion coatings were formulated mainly, using maltodextrin as the structu ral material and a blend of surface-active compounds with a hyrophile-lipop hile balance of 6.0 as the dispersed phase, The effect an the water vapor p ermeability of the coatings was determined as a function, of disperse phase concentration, film thickness and relative humidity gradient. Results show ed that the coatings were stable even in relative humidity gradients of 92- 86%. Water vapor permeability values increased from 23.4 to 45.3 g.mm/kPa.d .m(2) when the dispersed phase was reduced from 0.20 to 0.10. A relative hu midity gradient of 92-86% produced a permeability of 79.6 higher than 63.6. g.mm/kPa.d.m(2) obtained with an 82-53% relative humidity gradient.