Dilution method study on the interfacial composition and structural parameters of water/C12-EOx-C12.2Br/n-hexanol/n-heptane microemulsions: effect of the oxyethylene groups in the spacer.

The interfacial composition and the structure of the water/C(12)-EO(x)-C(12).2Br/n-hexanol/n-heptane microemulsion have been investigated by the dilution method. The results showed that C(12)-EO(x)-C(12).2Br formed a stable water/oil microemulsion with the assistance of n-hexanol. Owing to the relatively large size of the head group, more n-hexanol molecules are populated on the droplet surface than in the C(12)-2-C(12).2Br system. The radius of the water pool of the C(12)-EO(3)-C(12).2Br system is not as sensitive to W(0) as in the C(12)-2-C(12).2Br system. Another feature of the present system is that its droplet size is considerably smaller than that of the C(12)-2-C(12).2Br system, and also those of the CPC and CTAB systems at relative high water content. This provides a potential application for the synthesis of nanoparticles with small size.