Preparation and properties of microemulsion detergent with linear medium chain fatty alcohols as oil phase

Abstract

The formation of promising oil-in-water microemulsion as detergent has been achieved by using linear medium chain fatty alcohols (C5-C8) as the oil phase, sodium dodecyl sulfate (SDS) and isomeric alcohol ethoxylate (IC13EO6) as a mixed surfactant, and 1-butanol as cosurfactant. Pseudoternary phase diagrams were constructed by addition of the water. The effect of the SDS to IC13EO6 mixing ratio on single phase microemulsion area size was systematically investigated. The structure transition of the microemulsion was measured by conductivity. The results show that with addition of the water, the structure of microemulsion transformed from water-in-oil, bicontinuous to oil-in-water. After diluted 500 times, the equilibrium contact angle and dynamic surface tension of the microemulsion were much lower than this for standard liquid detergent under the same condition indicating that the dilute microemulsion exhibited excellent spreading and wetting properties on hydrophobic surfaces. The detergency of the as-prepared microemulsions with different oil types was tested by Terg-O-Tometer in order to select optimum formulations from the infinite dilution zone. With optimum formulations, the detergency of microemulsion was higher than that of standard liquid detergents, because microemulsions exhibit strong solubilization ability on oil stain.