The Adsorption of Hydroxyl Mixed Ether Nonionic Polymeric Surfactants at Air/Water and Solid/Water Interfaces: Influence of Surfactant Molecular Structure

Abstract

AbstractThis paper reports the adsorption of four nonionic Hydroxyl Mixed Ether (HME) polymeric surfactants at air/water and solid/water interfaces. The characteristics of these nonionic surfactants, including surface tension, critical micelle concentration (CMC) and adsorption onto saponite and Teflon are investigated. At the air/water interface, the surface activity of the HME‐surfactants decreases with an increasing degree of ethoxylation. The surface tension results indicate that CMC, surface tension at CMC (γCMC), and the minimum surface area per adsorbed HME‐surfactant molecule (Amin) all increased with the degree of ethoxylation for surfactants with similar hydrocarbon chain lengths. Additionally, a strong adsorption onto the saponite (synthetic clay) was measured and found dependent on both the degree of ethoxylation and the hydrocarbon chain length. This adsorption was also observed by atomic force microscopy (AFM). On the other hand, the adsorption of HME‐surfactants on Teflon was independent of the hydrocarbon chain length.