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Elucidating the effect of additives on the alkyl chain packing of a double tail cationic surfactant

Gonçalves, Rui A.; Lindman, B. LU ; Miguel, M. G. LU ; Iwata, T. and Lam, Yeng Ming (2018) In Journal of Colloid and Interface Science 528. p.400-409
Abstract

Hypothesis: Some low molecular weight additives can strongly influence the phase behavior of aqueous surfactant systems, and this offers an important handle to control the properties of surfactant solutions and thus to optimize the stability and performance of various formulations. Experiments: The surfactant dioctadecyldimethylammonium chloride (DODAC) self-assembles into two lamellar phases in water, the gel phase (Lβ) and the liquid crystalline phase (Lα). Here, we present approaches to tune the gel-to-liquid crystalline transition temperature (Tm) with the use of additives. The effects of urea, sodium butyrate and butyric acid on the packing behavior of DODAC were determined. The surfactant phases... (More)

Hypothesis: Some low molecular weight additives can strongly influence the phase behavior of aqueous surfactant systems, and this offers an important handle to control the properties of surfactant solutions and thus to optimize the stability and performance of various formulations. Experiments: The surfactant dioctadecyldimethylammonium chloride (DODAC) self-assembles into two lamellar phases in water, the gel phase (Lβ) and the liquid crystalline phase (Lα). Here, we present approaches to tune the gel-to-liquid crystalline transition temperature (Tm) with the use of additives. The effects of urea, sodium butyrate and butyric acid on the packing behavior of DODAC were determined. The surfactant phases were characterized using polarized optical microscopy (POM), differential scanning calorimetry (DSC), and small/wide angle X-ray scattering (SWAXS). Findings: All three additives - urea, sodium butyrate and butyric acid yield a single and stable lamellar phase. Urea and sodium butyrate have only minor effects on Tm, butyric acid gives a large decrease as it stabilizes the Lα phase with respect to the Lβ phase. From the bilayer thickness of the gel phase an interdigitated or tilted packing of the surfactant molecules is suggested. The addition of sodium butyrate gives a highly interdigitated gel structure and resulted in the transition from lamellar liquid crystal to an isotropic L3 phase.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Additives, DODAC, Lamellar structure, Transition temperature
in
Journal of Colloid and Interface Science
volume
528
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85047957260
ISSN
0021-9797
DOI
language
English
LU publication?
yes
id
fdb763d7-3de9-4a3a-848f-5b38b4df3476
date added to LUP
2018-06-11 10:06:33
date last changed
2018-06-12 03:00:02
@article{fdb763d7-3de9-4a3a-848f-5b38b4df3476,
  abstract     = {<p>Hypothesis: Some low molecular weight additives can strongly influence the phase behavior of aqueous surfactant systems, and this offers an important handle to control the properties of surfactant solutions and thus to optimize the stability and performance of various formulations. Experiments: The surfactant dioctadecyldimethylammonium chloride (DODAC) self-assembles into two lamellar phases in water, the gel phase (L<sub>β</sub>) and the liquid crystalline phase (L<sub>α</sub>). Here, we present approaches to tune the gel-to-liquid crystalline transition temperature (T<sub>m</sub>) with the use of additives. The effects of urea, sodium butyrate and butyric acid on the packing behavior of DODAC were determined. The surfactant phases were characterized using polarized optical microscopy (POM), differential scanning calorimetry (DSC), and small/wide angle X-ray scattering (SWAXS). Findings: All three additives - urea, sodium butyrate and butyric acid yield a single and stable lamellar phase. Urea and sodium butyrate have only minor effects on T<sub>m</sub>, butyric acid gives a large decrease as it stabilizes the L<sub>α</sub> phase with respect to the L<sub>β</sub> phase. From the bilayer thickness of the gel phase an interdigitated or tilted packing of the surfactant molecules is suggested. The addition of sodium butyrate gives a highly interdigitated gel structure and resulted in the transition from lamellar liquid crystal to an isotropic L<sub>3</sub> phase.</p>},
  author       = {Gonçalves, Rui A. and Lindman, B. and Miguel, M. G. and Iwata, T. and Lam, Yeng Ming},
  issn         = {0021-9797},
  keyword      = {Additives,DODAC,Lamellar structure,Transition temperature},
  language     = {eng},
  month        = {10},
  pages        = {400--409},
  publisher    = {Elsevier},
  series       = {Journal of Colloid and Interface Science},
  title        = {Elucidating the effect of additives on the alkyl chain packing of a double tail cationic surfactant},
  url          = {http://dx.doi.org/},
  volume       = {528},
  year         = {2018},
}