Microstructure of Mixed Nonionic Surfactants Microemulsions Studied By SAXS and DLS

Abstract

The systems investigated by small angle x-ray scattering, and dynamic light scattering were water/sucrose laurate/ethoxylated mono-di-glyceride/oleic phase. The oleic phases were oil or (oil + ethanol). The oils were R (+)-limonene and isopropylmyristate. The mixing ratios (w/w) of sucrose laurate/ethoxylated mono-di-glyceride and that of ethanol/oil equal unity. Small angle x-ray scattering results indicate that the periodicity increases linearly with the increase in the water volume fraction in these microemulsions. The correlation length increases with the increase in the water volume fraction to a certain value then decreases. The presence of ethanol in the microemulsions decreases the droplets size. Dynamic light scattering results at 298 K of the water/sucrose laurate/ethoxylated mono-di-glyceride/oil + ethanol microemulsions samples formulated in the presence of 90 wt% water indicated particle radii of 8 and 9 nm for the systems based on R(+)-limonene and isopropylmyristate, respectively. The hydrodynamic radius obtained by dynamic light scattering for diluted microemulsions increases with the increase of temperature.

Keywords:

• Amphiphilicity factor
• correlation length
• droplet size
• hydrodynamic radius
• periodicity
• phase behavior
• scattering intensity
• surfactants mixing ratio