Clouding Behaviour of Polysorbate 80: Effect of Additives

Abstract Polysorbate 80 and sodium lauryl ether sulphate mixtures are often used in personal care products especially in shampoo formulations. In this paper, the combined effect of sodium lauryl ether sulphate and salts (Na 2 SO 4 , NaCl, CaCl 2 ) and sodium lauryl ether sulphate and alcohols having different chain length on the cloud point of polysorbate 80 has been studied. The cloud point of a nonionic surfactant is influenced by the presence of additives. In the current system, a rise in the cloud point of polysorbate 80 was observed in the presence of ionic surfactant, sodium lauryl ether sulphate (0.010–0.050 mM) which is interpreted as increase in the surface charge of micelle. The cloud point of the sodium lauryl ether sulphate-polysorbate 80 mixture decreased with the addition of inorganic salts. The presence of short chain alcohols (C 1 –C 3 ) was found to increase the cloud point of polysorbate 80-sodium lauryl ether sulphate mixtures whereas, long chain alcohols (C 4 , C 5 ) were found to decrease the cloud point of polysorbate 80-sodium lauryl ether sulphate mixtures depending on their solubility in water.