PEO-related block copolymer surfactants

Non-ionic block copolymer systems based on hydrophilic poly(ethylene oxide) and more hydrophobic co-polymer blocks are used intensively in a variety of industrial and personal applications. A brief description on the applications is presented. The physical properties of more simple model systems of such PEG-based block copolymers in aqueous suspensions are reviewed. Based on scattering experiments using either X-ray or neutrons, the phase behavior is characterized, showing that the thermo-reversible gelation is a result of micellar ordering into mesoscopic crystalline phases of cubic, hexagonal or lamellar nature. Shear has major effect on the crystalline texture, but seems not to change the thermodynamic stable phases significantly. (C) 2001 Elsevier Science B.V. All rights reserved.