Phase behavior of concentrated hydroxypropyl methylcellulosesolution in the presence of mono and divalent salt

tThermo reversible sol–gel transitions of hydroxypropylmethylcellulose (HPMC) are critical for manypharmaceutical, cosmetic, and food applications. This study examined the effects of salt (NaCl and CaCl2)on the viscoelastic properties of concentrated low molecular weight HPMC solutions and found that thegelation temperature decreased linearly as a function of salt concentrations, independent of valency ofcations and the mole concentration of anions. Thermal analysis showed that the depression of meltingtemperature can be fitted for both NaCl and CaCl2as a function of the total number of ions by a singlelinear curve, which was consistent with the melting point depression of pure water by NaCl and CaCl2,but with a higher linear slope.