PEO-brush at the liquid:gas interface
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : Rossen Sedev *
- چاپ و سال / کشور: 1999
Description
Water-soluble amphiphilic polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) triblock copolymers (pluronics and synperonics) are used to build a PEO-brush at the aqueous solution:air interface. Microscopic foam films are formed from these solutions and their equilibrium thickness h is measured. Under certain conditions (high electrolyte concentration and low capillary pressure) h can be taken as a measure of the PEO-brush thickness L0: h:2L0. The results are in general agreement with the simple brush theory. However an additional influence of polymeric surfactants’ asymmetry is observed. Qualitatively this effect can be attributed to the self-assembly character of adsorption at the fluid interface, i.e. the competition between adsorption of PPO blocks and stretching of PEO chains. Results for low molecular EO-containing surfactants are also in line with the above findings. © 1999 Elsevier Science B.V. All rights reserved.
Colloids and Surfaces A: Physicochemical and Engineering Aspects 156 (1999) 65–70 Received 2 July 1998; accepted 27 November 1998
