Polyelectrolyte and surfactant mixed solutions. Behavior at surfaces and in thin films |
| |
Institution: | 1. Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra 2600, Australia;2. School of Physical, Environmental & Mathematical Sciences, UNSW Canberra, ACT 2610, Australia;3. Department of Chemistry “Ugo Schiff” University of Florence, 50019 Sesto Fiorentino, Firenze, Italy |
| |
Abstract: | Dilute mixed solutions of non-surface active anionic polymers (polyacrylamide and polystyrene sulfonate, xanthan) and various surfactants have been studied with several methods: surface tension, ellipsometry, X-ray and neutron reflectivity, thin film balance, surface and bulk rheology. A strong synergistic lowering of the surface tension is found with cationic surfactants in the concentration range where no appreciable complexation of surfactant and polymer occurs in the bulk solution (as seen from viscosity measurements). Despite appreciable differences between surface tension behaviour, the adsorbed layer is very similar for all the polymers: their thickness is small and the polymer chains are stretched along the surface. The surface tension behaviour of these polymers with non-ionic surfactants is also different. When the polymers are confined in thin films, the forces between surfaces are similar, and independent of surfactant nature: oscillatory forces are measured, which reflect the existence of a polymer network with a well defined mesh size. The connection of foam stability with surface and bulk complexation is far from clear. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|