Abstract:

The dynamic dilational viscoelasticity properties of N-2-(phenoxy)-tetradecanolytaurinate (12+B-T) and N-2-(4-ethylphenoxy)-tetradecanolytaurinate (12+2B-T) at the air/water interface were investigated by drop shape analysis and their foam properties were measured. The influence of time, dilational frequency, and bulk molar concentration on the surface dilational modulus and phase angle were investigated. A molecular interaction controls the nature of the film's adsorption at the lower concentration range and the filmis elastic in nature. At a higher concentration range, a diffusion exchange process controls the dynamic dilational properties and the surface film shows remarkable viscoelasticity. The addition of one ethyl group to the benzene ring enhances the molecular interaction which results in increases of the dilational modulus and foamstability.

Key words: Phase angle, Aromatic side chained N-acyltaurate, Surface, Dilational modulus, Foaming property