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Micellar crowding and branching in a versatile catanionic system

Asaro, Fioretta ; Coppola, Luigi and Gentile, Luigi LU (2016) In Colloids and Surfaces A: Physicochemical and Engineering Aspects 506. p.202-209
Abstract

The catanionic system didodecyldimethylammonium bromide (DDAB)-sodium taurodeoxycholate (STDC)-D2O is characterized by an exceptionally extended L1 region. The comparison of self-diffusion coefficient of the solvent and the DDAB embedded in the micelles provided information about hydration of the aggregates. Moreover, correlating self-diffusion and 14N NMR relaxation measurements new insight could be obtained regarding the translational and rotational micellar motions in the crowded solutions of systems with 0.2 DDAB-STDC molar ratio. 1H 2D NMR spectra gave some hints about the mutual arrangement of DDAB and STDC within the aggregates. For samples with 1.8 and 2.6 DDAB/STD molar ratios the... (More)

The catanionic system didodecyldimethylammonium bromide (DDAB)-sodium taurodeoxycholate (STDC)-D2O is characterized by an exceptionally extended L1 region. The comparison of self-diffusion coefficient of the solvent and the DDAB embedded in the micelles provided information about hydration of the aggregates. Moreover, correlating self-diffusion and 14N NMR relaxation measurements new insight could be obtained regarding the translational and rotational micellar motions in the crowded solutions of systems with 0.2 DDAB-STDC molar ratio. 1H 2D NMR spectra gave some hints about the mutual arrangement of DDAB and STDC within the aggregates. For samples with 1.8 and 2.6 DDAB/STD molar ratios the 14N data were in agreement with the presence of somewhat branched, interconnected micelles. 23Na and 81Br dynamic parameters resulted particularly sensitive to the surrounding environment. The peculiar rheological behaviour of the, highly concentrated, branched micelles samples, namely the steady oscillations in the step tests, was found to be an example of instability originated by the combined effect of material elasticity and slippage at the fixed wall.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Bile salts, Flow instability, NMR relaxation, NMR-diffusometry, Rheology
in
Colloids and Surfaces A: Physicochemical and Engineering Aspects
volume
506
pages
8 pages
publisher
Elsevier
external identifiers
  • scopus:84977508320
ISSN
0927-7757
DOI
10.1016/j.colsurfa.2016.06.035
language
English
LU publication?
yes
id
6363cc43-c2e0-415c-a949-452c09349da9
date added to LUP
2022-03-30 13:44:57
date last changed
2022-03-30 17:00:48
@article{6363cc43-c2e0-415c-a949-452c09349da9,
  abstract     = {{<p>The catanionic system didodecyldimethylammonium bromide (DDAB)-sodium taurodeoxycholate (STDC)-D<sub>2</sub>O is characterized by an exceptionally extended L<sub>1</sub> region. The comparison of self-diffusion coefficient of the solvent and the DDAB embedded in the micelles provided information about hydration of the aggregates. Moreover, correlating self-diffusion and <sup>14</sup>N NMR relaxation measurements new insight could be obtained regarding the translational and rotational micellar motions in the crowded solutions of systems with 0.2 DDAB-STDC molar ratio. <sup>1</sup>H 2D NMR spectra gave some hints about the mutual arrangement of DDAB and STDC within the aggregates. For samples with 1.8 and 2.6 DDAB/STD molar ratios the <sup>14</sup>N data were in agreement with the presence of somewhat branched, interconnected micelles. <sup>23</sup>Na and <sup>81</sup>Br dynamic parameters resulted particularly sensitive to the surrounding environment. The peculiar rheological behaviour of the, highly concentrated, branched micelles samples, namely the steady oscillations in the step tests, was found to be an example of instability originated by the combined effect of material elasticity and slippage at the fixed wall.</p>}},
  author       = {{Asaro, Fioretta and Coppola, Luigi and Gentile, Luigi}},
  issn         = {{0927-7757}},
  keywords     = {{Bile salts; Flow instability; NMR relaxation; NMR-diffusometry; Rheology}},
  language     = {{eng}},
  pages        = {{202--209}},
  publisher    = {{Elsevier}},
  series       = {{Colloids and Surfaces A: Physicochemical and Engineering Aspects}},
  title        = {{Micellar crowding and branching in a versatile catanionic system}},
  url          = {{http://dx.doi.org/10.1016/j.colsurfa.2016.06.035}},
  doi          = {{10.1016/j.colsurfa.2016.06.035}},
  volume       = {{506}},
  year         = {{2016}},
}