This might due to the bulky and strongly anionic nature of monostarch phosphates (STPP) in the HPC2 which leads to cold water swelling when the DS increased [49]. The HPC2 had a higher amount of phosphorus content (Table 1) than with 2% STMP only. It is believed that the high level of phosphate groups in the HPC2 induced the ionic character and ready hydration in water Thus the HPC2 films showed higher WVP values than did the HPC1 [14].