Mechanisms behind the faceting of catanionic vesicles by polycations: Chain crystallization and segregation
(2007) In The Journal of Physical Chemistry Part B 111(1). p.116-123- Abstract
- Vesicles composed of an anionic and a cationic surfactant, with a net negative charge, associate strongly with a hydrophobically modified polycation (LM200) and with an unmodified polycation with higher charge density (JR400), forming viscoelastic gel-like structures. Calorimetric results show that in these gels, LM200 induces a rise of the chain melting temperature (T-m) of the vesicles, whereas JR400 has the opposite effect. For both polymer-vesicle systems, the shear viscosity exhibits an inflection point at T-m, and for the LM200 system the measured relaxation times are significantly higher below T-m. The neat vesicles and the polycation-bound vesicles have a polygonal-like faceted shape when the surfactant chains in the bilayer are... (More)
- Vesicles composed of an anionic and a cationic surfactant, with a net negative charge, associate strongly with a hydrophobically modified polycation (LM200) and with an unmodified polycation with higher charge density (JR400), forming viscoelastic gel-like structures. Calorimetric results show that in these gels, LM200 induces a rise of the chain melting temperature (T-m) of the vesicles, whereas JR400 has the opposite effect. For both polymer-vesicle systems, the shear viscosity exhibits an inflection point at T-m, and for the LM200 system the measured relaxation times are significantly higher below T-m. The neat vesicles and the polycation-bound vesicles have a polygonal-like faceted shape when the surfactant chains in the bilayer are crystallized, as probed by cryo-transmission electron microscopy. Above T-m, the neat and the LM200-bound vesicles regain a spheroidal shape, whereas those in the JR400 system remain with a deformed faceted shape even above T-m. These shape changes are interpreted in terms of different mechanisms for the polymer-vesicle interaction, which seem to be highly dependent on polymer architecture, namely charge density and hydrophobic modification. A crystallization-segregation mechanism is proposed for the LM200-vesicle system, while, for the JR400-vesicle one, charge polarization-lateral segregation effects induced by the polycation in the catanionic bilayer are envisaged. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/680012
- author
- Antunes, Filipe LU ; Brito, Rodrigo O. ; Marques, Eduardo LU ; Lindman, Björn LU and Miguel, Maria LU
- organization
- publishing date
- 2007
- type
- Contribution to journal
- publication status
- published
- subject
- in
- The Journal of Physical Chemistry Part B
- volume
- 111
- issue
- 1
- pages
- 116 - 123
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000243229400015
- scopus:33847093044
- ISSN
- 1520-5207
- DOI
- 10.1021/jp063994
- language
- English
- LU publication?
- yes
- id
- 5f1e9955-dd98-4c36-b3be-8f1946da04db (old id 680012)
- date added to LUP
- 2016-04-01 16:41:45
- date last changed
- 2022-01-28 21:28:36
@article{5f1e9955-dd98-4c36-b3be-8f1946da04db,
abstract = {{Vesicles composed of an anionic and a cationic surfactant, with a net negative charge, associate strongly with a hydrophobically modified polycation (LM200) and with an unmodified polycation with higher charge density (JR400), forming viscoelastic gel-like structures. Calorimetric results show that in these gels, LM200 induces a rise of the chain melting temperature (T-m) of the vesicles, whereas JR400 has the opposite effect. For both polymer-vesicle systems, the shear viscosity exhibits an inflection point at T-m, and for the LM200 system the measured relaxation times are significantly higher below T-m. The neat vesicles and the polycation-bound vesicles have a polygonal-like faceted shape when the surfactant chains in the bilayer are crystallized, as probed by cryo-transmission electron microscopy. Above T-m, the neat and the LM200-bound vesicles regain a spheroidal shape, whereas those in the JR400 system remain with a deformed faceted shape even above T-m. These shape changes are interpreted in terms of different mechanisms for the polymer-vesicle interaction, which seem to be highly dependent on polymer architecture, namely charge density and hydrophobic modification. A crystallization-segregation mechanism is proposed for the LM200-vesicle system, while, for the JR400-vesicle one, charge polarization-lateral segregation effects induced by the polycation in the catanionic bilayer are envisaged.}},
author = {{Antunes, Filipe and Brito, Rodrigo O. and Marques, Eduardo and Lindman, Björn and Miguel, Maria}},
issn = {{1520-5207}},
language = {{eng}},
number = {{1}},
pages = {{116--123}},
publisher = {{The American Chemical Society (ACS)}},
series = {{The Journal of Physical Chemistry Part B}},
title = {{Mechanisms behind the faceting of catanionic vesicles by polycations: Chain crystallization and segregation}},
url = {{http://dx.doi.org/10.1021/jp063994}},
doi = {{10.1021/jp063994}},
volume = {{111}},
year = {{2007}},
}