The adsorption of hydrophobically modified polyacrylates at interfaces of quartz/liquid and gas/liquid

The properties of hydrophobically modified polyacrylates (HMPAs) at the interfaces of quartz/liquid and gas/liquid (g/l) are studied. From the determination of contact angle, adsorption isotherm and atomic force microscopy (AFM) images, the adsorption mechanism of HMPAs on the quartz surface is discussed. The hydrophilicity of quartz increases with the adsorption of HMPAs, which shows that they are adsorbed to the surface by hydrogen bond between carboxyl and quartz and the hydrophilic groups direct toward the bulk solution. In addition, there appear the island-like aggregates at lower concentration and with the concentration increasing above critical micelle concentration (cmc) large micelle-like clusters of HMPAs are observed on the quartz surface from the AFM images. The results of surface tension and surface pressure measurements show the HMPAs are easy to pack tightly at the g/l interface, which leads to the remarkable decrease of surface tension of water. Moreover the capability of HMPAs to form film is good.