Surface tension of aqueous solutions of alcohol and polyols at 298.15 K

Surface tension of aqueous solutions of 1-propanol (nP), 1,2-propanediol (12PD), 1,3-propanediol (13PD) and 1,2,3-propanetriol (123PT) were measured using the method of capillary rise as a function of concentration at 298.15 K with emphasis in the very dilute region. The decrease of surface tension with mole fraction of alcohol becomes less pronounced as the number of OH groups increases. The surface enrichment effect, reflected by the slopes for the curves of surface tension versus composition, is correlated with the number of hydroxyl groups in the solute and the hydrophilic character of the solutes.