Gels of hydrophobically modified hydroxyethyl cellulose cross-linked by amylose: Competition by added surfactants

Monica Egermayer, Jens Norrman, Lennart Piculell

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9 Citations (SciVal)

Abstract

Previous work has shown that amylose (AM) can cross-link hydrophobically modified polymers by inclusion complexation, whereby thermoreversible cold-setting gels are formed. This work investigates, mainly by rheology, the competition effect of seven different anionic, cationic, and nonionic surfactants when mixed at room temperature into preformed gels of AM and hydrophobically modified hydroxyethyl celluose (HMHEC). The aqueous mixtures of AM, HMHEC, and surfactant are compared with reference mixtures of AM-HMHEC, AM-surfactant, and HMHEC-surfactant, respectively. All the added surfactants interact with HMHEC, giving rise to the well-known increase in shear storage modulus compared to pure HMHEC solution. In addition, all added surfactants, except Triton X-100, form inclusion complexes with AM. The mechanical spectra of the AM/HMHEC/surfactant mixtures are closely similar to those containing only HMHEC and surfactant but quite distinct from that of the AM-HMHEC gel, demonstrating that all surfactants can compete with the AM-HMHEC complexation. Heat treatment of the mixtures produced no significant changes. A detailed analysis of the competition by two surfactants, sodium dodecyl sulfate (SDS) and sodium octyl sulfate (SOS), showed that much larger amounts of added SOS were required for an efficient competition. The rheological characteristics indicate that the HMHEC hydrophobes are simultaneously engaged i
both mixed micelles with the added surfactant and inclusion complexes with AM over a large concentration range of added surfactant.
Original languageEnglish
Pages (from-to)10036-10043
JournalLangmuir
Volume19
Issue number24
DOIs
Publication statusPublished - 2003

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Physical Chemistry 1 (S) (011001006), Center for Chemistry and Chemical Engineering (011001000)

Subject classification (UKÄ)

  • Physical Chemistry

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