MEASUREMENT OF THE PARTITION-COEFFICIENT OF SURFACTANTS IN WATER OIL SYSTEMS/

The partition coefficients between water and hexane of some n-alkyldim ethylphosphine oxides (C-n-DMPO) and octylphenyl poly(ethylene glycol) ethers (Triton X-100 and Triton X-405) and of one poly(oxyethylene) c etyl ether (C16E20) have been determined by using an indirect techniqu e based on the measurement of the surface tension of the aqueous surfa ctant solution after equilibration with the second liquid phase. Thoug h some of the surfactants studied have been described in the past as i nsoluble in alkanes, the results show that at monomeric concentrations , most of them have a non-zero value of the partition coefficient. The se results are particularly important when dynamics adsorption phenome na at liquid-liquid interfaces are concerned.