Water-in-CO2 microemulsions studied by small-angle neutron scattering

Julian Eastoe; Beatrice M.H. Cazelles; David C. Steytler; Justin D. Holmes; Alan R. Pitt; Trevor J. Wear; Richard K. Heenan

doi:10.1021/la970876s

Water-in-CO₂ microemulsions studied by small-angle neutron scattering

Julian Eastoe
, Beatrice M.H. Cazelles
, David C. Steytler
, Justin D. Holmes
, Alan R. Pitt
, Trevor J. Wear
, Richard K. Heenan

Research output: Contribution to journal › Article › peer-review

Abstract

Aggregate structures in water-in-CO₂ microemulsions were studied by high-pressure small-angle neutron scattering (SANS). With liquid CO₂ at 15 °C, the partially fluorinated, di-chain surfactant bis(1H,1H,5H-octafluoro-n-pentyl) sodium sulfosuccinate (di-HCF4) stabilized single-phase microemulsions at pressures above ∼400 bar. The maximum water loading (w) investigated was 30 ([water]/[di-HCF4]), representing formation of relatively large water droplets in the microemulsion. Between w = 5 and 30, the SANS data were consistent with a model for attractive polydisperse spherical droplets. A linear relationship between the water droplet radius (R_c) and w was found, which gave an apparent head group area for the surfactant of 87 Å² at the water-CO₂ interface. In Winsor II type microemulsions the value of R_c, measured in the presence of excess water, increased with pressure from 36 Å at 400 bar to 56 Å at 550 bar.

Original language	English
Pages (from-to)	6980-6984
Number of pages	5
Journal	Langmuir
Volume	13
Issue number	26
DOIs	https://doi.org/10.1021/la970876s
Publication status	Published - 24 Dec 1997
Externally published	Yes

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@article{cce5c7b355db4cccb8c314c2e23711b9,

title = "Water-in-CO2 microemulsions studied by small-angle neutron scattering",

abstract = "Aggregate structures in water-in-CO2 microemulsions were studied by high-pressure small-angle neutron scattering (SANS). With liquid CO2 at 15 °C, the partially fluorinated, di-chain surfactant bis(1H,1H,5H-octafluoro-n-pentyl) sodium sulfosuccinate (di-HCF4) stabilized single-phase microemulsions at pressures above ∼400 bar. The maximum water loading (w) investigated was 30 ([water]/[di-HCF4]), representing formation of relatively large water droplets in the microemulsion. Between w = 5 and 30, the SANS data were consistent with a model for attractive polydisperse spherical droplets. A linear relationship between the water droplet radius (Rc) and w was found, which gave an apparent head group area for the surfactant of 87 {\AA}2 at the water-CO2 interface. In Winsor II type microemulsions the value of Rc, measured in the presence of excess water, increased with pressure from 36 {\AA} at 400 bar to 56 {\AA} at 550 bar.",

author = "Julian Eastoe and Cazelles, \{Beatrice M.H.\} and Steytler, \{David C.\} and Holmes, \{Justin D.\} and Pitt, \{Alan R.\} and Wear, \{Trevor J.\} and Heenan, \{Richard K.\}",

year = "1997",

month = dec,

day = "24",

doi = "10.1021/la970876s",

language = "English",

volume = "13",

pages = "6980--6984",

journal = "Langmuir",

issn = "0743-7463",

publisher = "American Chemical Society",

number = "26",

}

TY - JOUR

T1 - Water-in-CO2 microemulsions studied by small-angle neutron scattering

AU - Eastoe, Julian

AU - Cazelles, Beatrice M.H.

AU - Steytler, David C.

AU - Holmes, Justin D.

AU - Pitt, Alan R.

AU - Wear, Trevor J.

AU - Heenan, Richard K.

PY - 1997/12/24

Y1 - 1997/12/24

N2 - Aggregate structures in water-in-CO2 microemulsions were studied by high-pressure small-angle neutron scattering (SANS). With liquid CO2 at 15 °C, the partially fluorinated, di-chain surfactant bis(1H,1H,5H-octafluoro-n-pentyl) sodium sulfosuccinate (di-HCF4) stabilized single-phase microemulsions at pressures above ∼400 bar. The maximum water loading (w) investigated was 30 ([water]/[di-HCF4]), representing formation of relatively large water droplets in the microemulsion. Between w = 5 and 30, the SANS data were consistent with a model for attractive polydisperse spherical droplets. A linear relationship between the water droplet radius (Rc) and w was found, which gave an apparent head group area for the surfactant of 87 Å2 at the water-CO2 interface. In Winsor II type microemulsions the value of Rc, measured in the presence of excess water, increased with pressure from 36 Å at 400 bar to 56 Å at 550 bar.

AB - Aggregate structures in water-in-CO2 microemulsions were studied by high-pressure small-angle neutron scattering (SANS). With liquid CO2 at 15 °C, the partially fluorinated, di-chain surfactant bis(1H,1H,5H-octafluoro-n-pentyl) sodium sulfosuccinate (di-HCF4) stabilized single-phase microemulsions at pressures above ∼400 bar. The maximum water loading (w) investigated was 30 ([water]/[di-HCF4]), representing formation of relatively large water droplets in the microemulsion. Between w = 5 and 30, the SANS data were consistent with a model for attractive polydisperse spherical droplets. A linear relationship between the water droplet radius (Rc) and w was found, which gave an apparent head group area for the surfactant of 87 Å2 at the water-CO2 interface. In Winsor II type microemulsions the value of Rc, measured in the presence of excess water, increased with pressure from 36 Å at 400 bar to 56 Å at 550 bar.

UR - https://www.scopus.com/pages/publications/0031331956

U2 - 10.1021/la970876s

DO - 10.1021/la970876s

M3 - Article

AN - SCOPUS:0031331956

SN - 0743-7463

VL - 13

SP - 6980

EP - 6984

JO - Langmuir

JF - Langmuir

IS - 26

ER -

Water-in-CO₂ microemulsions studied by small-angle neutron scattering

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