Interactions of ethylene oxide/methylene oxide copolymers with sodium dodecyl sulphate

The interactions of poly(1,3,6,9-tetraoxacycloundccane) (PTGF) and poly(1,3,6-trioxacyclooctane) (PDGF) with sodium dodecyl sulphate (SDS) were studied by conductimetry, viscosimetry and fluorescence. The results are compared to those obtained in the cases of poly(ethyleneoxide) (PEO) and poly(1,3-dioxolane) (PDXL). The total amount of SDS bound along the polymer chain is found to decrease when the molar fraction of methylene oxide units (MO) increases, while the aggregation number of the bound micelles becomes much lower. Besides, when the polymer has a poor water solubility, addition of SDS improves this solubility, the lower critical solution temperature (LCST) being an increasing function of the SDS concentration. These results suggest that ethylene oxide (EO) units are mainly responsible for the SDS binding and that the absence of long EO sequences in PDXL hinders the micelle growth. (C) 2000 Elsevier Science Ltd. All rights reserved.