Study of the cloud point of C12En nonionic surfactants: effect of additives

Nonionic surfactants are useful in the formation of emulsions. The aqueous solutions of these surfactants show complex phase behaviour including liquid–liquid phase separation at higher temperature. Addition of foreign substance to surfactant solutions does change the temperature at which the clouding phenomena occurs. In this article, we report the effect of electrolytes as well as nonelectrolytes on the cloud point (CP) of a series of nonionic surfactants of the poly(oxyethylene)ether type C12En (n=6, 9, 10). It was observed that NaI and KI have different effect on the CP from that of NaCl, NaBr, KCl and KBr. Tetra butyl ammonium iodide (TBAI) acts differently on the CP from the Tetra methyl ammonium bromide (TMAB). Overall the electrolytes and nonelectrolytes have a large amount of effect on CP of nonionic surfactants, because of their effect on water structure and their hydrophilicity.