Effects of Additives on Water Solubilization Capacity and Intermicellar Interaction in Heptane/Hexanol/Tritonx-100/Water Microemulsion

Abstract

The water solubilization capacity (W₀) of microemulsion system determines its physicochemical properties and interior structures. In this study, the effects of different kinds of additives such as inorganic salt, nonaqueous polar solvent, organic salt, amino acid, and polyethylene glycols (PEG series) on the water solubilization behavior of heptane/hexanol/TritonX-100/water microemulsion system have been studied in detail. The influence mechanism of every additive on W₀ has also been proposed and discussed. Furthermore, the droplet size distribution and the interaction among the droplets have been investigated by dynamic light scattering technique with the presence of additives. The result shows that the hydrodynamic diameter of microemulsion droplet and the attractive interaction between the droplets increase with the increase of the water content and the additive concentration. This work presents a facile method to adjust the structure parameters and the interface strength of microemulsion system by adding additive to the system, and to direct the applications of microemulsion system in nanomaterials preparation and drug controlled release.

Keywords:

• Additive
• dynamic light scattering
• microemulsion
• water solubilization capacity

Acknowledgments

This work was supported by the National Natural Science Foundation of China (20776026, 21006008), Fundamental Research Funds for the Central Universities (893123), and New Century Excellent Talents in University (NCET-06-0272).

Notes

Note. The determination of diameter by DLS is impossible for NaCA system because of the polydispersity of the droplets.