The microstructural characteristics of colloidal liquid aphrons(CLA)composed of polyoxyethylene 3 dodecyl ether(AEO-3)/n-decane/sodium dodecyl sulphate(SDS)or Tween 80/water were investigated using attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR)and differential scanning calorimetry(DSC). The interaction of water or n-decane with SDS or AEO-3 in CLA and ordinary emulsions systems was analyzed at the molecular level. The results indicate that the aqueous and organic domains are separate at a molecular level. Both water and n-decane display three distinct states: free
interphasal and bound
respectively. Their relative amounts are found to depend on the volume ratio of organic phase to aqueous phase. The content of free water decreases with the increase of PVR
accompanying the interphasal and bound water to gradually increase. The mixed nonionic/anionic surfactants of AEO-3 and SDS contribute to the formation of CLA
which is distinct from the ordinary emulsion stabilized with only one type of surfactant.
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references
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