Abstract: The dilational viscoelastic properties of sodium N-2-(phenoxy)-tetradecanolytaurinate (12+B-T), sodium N-2-(4-ethylphenoxy)- tetradecanolytaurinate (12+2B-T) and sodium N-2-(4-hexylphenoxy)-tetradecanolytaurinate (12+6B-T) at the air/water and oil/water interfaces were investigated by interfacial tension relaxation method. The effect of aromatic side-chain length on interfacial behavior has been expounded. The influences of surfactant structures on the concentration dependences of limiting dilational elasticity, maximum of dilational viscosity and involving characteristic frequency have been obtained. It is found that 12+6B-T can form more elastic adsorption film at low bulk concentration and surface re-arrangement process controls the nature of film due to the existence of stronger interactions among longer length of aromatic side-chains. Diffusion-exchange process becomes to dominate interfacial behavior with the decrease of interactions by the increasing bulk concentration or the insertion of decane molecules.

Key words: Aromatic side chained N-acyltaurate, Relaxation process, Limiting dilational elasticity, Maximum of dilational viscosity, Surface, Interface