| Abstract: | A water-in-oil (w/o) microemulsion was prepared with the zwitterionic surfactant dodecyl betaine (C12BE), n-pentanol (C5OH), n-heptane (C7H16) and water. Effects of polyvinylpyrrolidone (PVP) with different molecular weight on the state of water in w/o microemulsions at a given water/C12BE molar ratio were investigated by FT-IR and differential scanning calorimetry (DSC). The experimental results showed that addition of PVP resulted in an increase of the content of the bound water in water pool of a w/o microemulsion, but a decrease of the amount of the bulky water. The higher the molecular weight of PVP, the more bound water; and the less bulk water. The change of the trapped water was not obvious due to the interference of C5OH. |
