(629c) Studies Of Dynamic Surface Tension Of Polyoxyethylene Alkylphenols At The Air-Water Interface

This paper presents the study of dynamic surface tension of polyoxyethylene alkylphenol surfactants at the air-solution interface. The experimental investigation of the surface tensions dynamics are carried out using a pendant drop method for two of the representative alkylphenols (Igepal-630 and Igepal-720) nonionic surfactants. The general trend of the dynamic surface tension for the two surfactants appears to be similar. However, the absolute surface activities are different. Between the two poloxyethylene alkylphenols surfactant, it was found that Igepal-C0-630 has the higher surface activity and the lower critical micelle concentration (CMC) values. This was well matched with their reported HLB (hydrophile-lipophile balance). The equilibrium adsorption parameters for these surfactant systems have been estimation using two different methods and are in good agreement. The theoretical model developed for the surface tension dynamics based on the Statistical Rate Theory (SRT) in our earlier (J. Colloid and Interface Science, 286, 2005, 14-27) work satisfactorily predicts the experimental results for the present systems.