Study on Foaming Properties of Polyoxyethylene Alkyl Ether Carboxylic Salts with Different Structures

In this article, foaming properties, dynamic surface tension, and surface dilational properties were carried out with aqueous solutions of polyoxyethylene alkyl ether carboxylic salts to elucidate the relationship between foaming properties and surfactant structures. It was found that the dynamic surface tension of the solution is the key factor in determining the foamability: with increasing in the length of the hydrophobic group, dynamic surface activity becomes low, which leads to the low foam volume; the surfactant with branched-alkyl chain has faster diffusion rate, which lead to higher dynamic surface activity and higher foam volume. However, for straight chain surfactant, the foam stability is correlated with the surface dilational properties: the change rule of surface dilational modulus is consistent with that of the foam stability.