The adsorption behaviour of some ethoxylated alkylphenolformaldehyde polymeric non-ionic surfactants, at the aqueous solution-air interface, was investigated by measuring the surface tension (y) as a function of concentration (C) at four temperatures. By applying the Gibbs adsorption equation to the y versus C data, the adsorption isotherms of these polymeric surfactants were obtained.Surface concentration (r) of the investigated polymeric non-ionics was found to increase with decreasing temperature and decreasing hydrophobic group (R) chain length, while varying the length of polyoxyethylene chain (% EO) appeared to have an insigificant effect. Effects of temperature, % EO and chain length R on the surface pressure (w) of the surfactant solutions were also investigated. K e y words: polymeric nonionic surfactants, ethoxylated alkylphenolformaldehyde, adsorption of polymeric nonionics

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The novel anionic surfactant sodium 3-oxo-2-(3-(4-sulphonatophenyl)triaz-2-enyl)octadecanoate (SSTO) was prepared from renewable raw materials; glycine and palmitic acid. Surface and bulk properties of SSTO were investigated by surface tension and electrical conductivity techniques at 298, 308, 318 and 328 K. Surface properties including critical micelle concentration (CMC), maximum surface excess concentration (C max ), minimum area per molecule (A min ), surface tension at CMC (c CMC ), effectiveness of surface tension reduction (P CMC ), efficiency of surface adsorption (pC 20 ), and degree of counterion dissociation (a) were determined. The thermodynamic parameters of micellization (DG°m ic , DH°m ic and DS°m ic ) and adsorption (DG°a d , DH°a d and DS°a d ) were also investigated at 298, 308, 318 and 328 K. The effect of 3 wt% n-propanol, n-butanol and n-pentanol on surface tension and conductivity at 298 K was also determined.

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