Advanced

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

Egermayer, Monica LU ; Norrman, Jens LU and Piculell, Lennart LU (2003) In Langmuir 19(24). p.10036-10043
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
19
issue
24
pages
10036 - 10043
publisher
The American Chemical Society
external identifiers
  • wos:000186694500010
  • scopus:0344082888
ISSN
0743-7463
DOI
10.1021/la0301689
language
English
LU publication?
yes
id
dc510605-a9db-46aa-84bf-cc71c893a2ee (old id 121978)
date added to LUP
2007-07-11 10:42:42
date last changed
2018-10-03 09:30:11
@article{dc510605-a9db-46aa-84bf-cc71c893a2ee,
  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<br/><br>
 both mixed micelles with the added surfactant and inclusion complexes with AM over a large concentration range of added surfactant.},
  author       = {Egermayer, Monica and Norrman, Jens and Piculell, Lennart},
  issn         = {0743-7463},
  language     = {eng},
  number       = {24},
  pages        = {10036--10043},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Gels of hydrophobically modified hydroxyethyl cellulose cross-linked by amylose: Competition by added surfactants},
  url          = {http://dx.doi.org/10.1021/la0301689},
  volume       = {19},
  year         = {2003},
}