1
|
Ta HY, Perquis L, Balayssac S, Déjugnat C, Wodrinski A, Collin F, Gilard V, Couderc F. Separation of unsaturated C18 fatty acids using perfluorinated-micellar electrokinetic chromatography: I. Optimization and separation process. Electrophoresis 2023; 44:431-441. [PMID: 36398472 PMCID: PMC10098715 DOI: 10.1002/elps.202200151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/27/2022] [Accepted: 11/09/2022] [Indexed: 11/19/2022]
Abstract
Ammonium perfluorooctanoate (APFOA) was used as a surfactant for the separation of free unsaturated C18 fatty acids by micellar electrokinetic chromatography. A simple background electrolyte of 50 mM APFOA water/methanol (90:10, v/v) at pH = 10 enabled the repeatable separation of oleic acid, elaidic acid, linoleic acid, and alpha-linolenic acid in less than 20 min. Separation conditions were optimized regarding various parameters (organic solvent, counterion, APFOA concentration, and pH). Because the repulsive interactions between fluorocarbon chains and hydrogenated chains are known to lead to segregation and phase separation, the choice of perfluorinated micelles to separate such perhydrogenated long-chain acids could appear astonishing. Therefore, the critical micelle concentration, the charge density, and the mobility of the micelles have been determined, resulting in a first description of the separation process.
Collapse
Affiliation(s)
- Hai Yen Ta
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Lucie Perquis
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Stéphane Balayssac
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Christophe Déjugnat
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Alexandre Wodrinski
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Fabrice Collin
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - Véronique Gilard
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| | - François Couderc
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, Toulouse, France
| |
Collapse
|
2
|
Zhu X, Jia X, Zhang Y, Luo Y, Bo H. Synthesis and Characterization of a Novel Short Fluorocarbon Chain Cationic Surfactant. J SURFACTANTS DETERG 2020. [DOI: 10.1002/jsde.12425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Xinhua Zhu
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Xuhong Jia
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Yuqiang Zhang
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Yuzhen Luo
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Haidong Bo
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| |
Collapse
|
3
|
Common black film stability and synergetic adsorption in ionic−nonionic mixed surfactant systems. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.123932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
4
|
Frotscher E, Höring J, Durand G, Vargas C, Keller S. Model-Free Analysis of Critical Micellar Concentrations for Detecting Demixing in Surfactant Mixtures. Anal Chem 2017; 89:3245-3249. [DOI: 10.1021/acs.analchem.7b00339] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Erik Frotscher
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Jonas Höring
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Grégory Durand
- Equipe
Chimie Bioorganique et Systèmes Amphiphiles, Université d’Avignon et des Pays de Vaucluse, 33 Rue Louis Pasteur, 84000 Avignon, France
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-UM-ENSCM, 15 Avenue Charles Flahault, 34093 Montpellier Cedex 05, France
| | - Carolyn Vargas
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| | - Sandro Keller
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663 Kaiserslautern, Germany
| |
Collapse
|
5
|
Investigation of mixed fluorinated and triblock copolymer liquid crystals: Imprint for mesostructured bimodal silica. J Colloid Interface Sci 2015; 446:170-6. [DOI: 10.1016/j.jcis.2015.01.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/14/2015] [Accepted: 01/14/2015] [Indexed: 11/17/2022]
|
6
|
Jackson AJ, Dong CC, Thomas RK, Penfold J. Unusual excess free energies of mixing in mixtures of partially fluorinated and hydrocarbon surfactants at the air-water interface: correlation with the structure of the layer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:272-282. [PMID: 25490580 DOI: 10.1021/la5043074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The air-water interface of three mixtures of partially fluorinated surfactants and hydrocarbon surfactants, C4F9C11H22N(CH3)3Br (fC4hC11TAB) with hexadecyltrimethylammonium bromide (C16TAB), (CF3)2C3F6C10H20N(CH3)3Br (fC5hC10TAB) with C16TAB, and C8F17C6H12N(CH3)3Br (fC8hC6TAB) with C18TAB, have been investigated using surface tension (ST) and neutron reflection (NR). Using the composition of the layer determined by NR, the pseudophase separation model was used to fit the variation of concentration for a specific ST to a free energy of mixing, G(E), that included adjustable quadratic, cubic and quartic terms. In all three cases, G(E) was found to be highly unsymmetrical, being approximately ideal at low surface fractions of hydrocarbon surfactant and repulsive at high fractions with a maximum value of 0.2-0.3RT. The corresponding structure of the layer was also determined by NR and showed that the initial ideal behavior of G(E) probably results from a balance of a gain in energy from a reduced immersion of the fluorocarbon chain, brought about by screening of the fluorocarbon from water by the hydrocarbon surfactant, and a loss from increased fluorocarbon-hydrocarbon repulsion. At higher concentration, there is no space in the layer for further screening and the fluorocarbon-hydrocarbon repulsion leads to the expected positive G(E). The calculated G(E) also indicated that there should be phase separation of the two components in the interface over a bulk composition range of about 60-95% hydrocarbon surfactant. However, experiment indicates no phase separation. It is suggested that there are a number of possible additional negative contributions to G(E) close to a phase transition, which are not possible for a true bulk phase separation, and which prevent surface phase separation unless it is strongly favored.
Collapse
Affiliation(s)
- Andrew J Jackson
- Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | | | | | | |
Collapse
|
7
|
Chen M, Dong C, Penfold J, Thomas RK, Smyth TJP, Perfumo A, Marchant R, Banat IM, Stevenson P, Parry A, Tucker I, Grillo I. Influence of calcium ions on rhamnolipid and rhamnolipid/anionic surfactant adsorption and self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:3912-3923. [PMID: 23445348 DOI: 10.1021/la400432v] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The impact of Ca(2+) counterions on the adsorption at the air-water interface and self-assembly in aqueous solution of the rhamnolipid biosurfactant and its mixture with the anionic surfactant sodium dodecylbenzenesulfonate, LAS, has been studied using neutron reflectometry and small-angle neutron scattering. The results illustrate how rhamnolipids are calcium tolerant and how their blending with conventional anionic surfactants improves the calcium tolerance of the anionic surfactant. Ca(2+) has relatively little effect upon the adsorption and self-assembly of the monorhamnose, R1, and dirhamnose, R2, rhamnolipids, even at high pH, due to their predominantly nonionic nature. For R1/R2 mixtures the addition of Ca(2+) has little impact upon the adsorbed amount or the surface composition. For R2/LAS mixtures the addition of Ca(2+) results in an increased adsorption and a surface slightly richer in R2. The weak binding of Ca(2+) to R1 and R2 does result in a change to the degree of ionization of the micelles and especially for mixed R1/R2 micelles at R1-rich solution compositions. The stronger binding of Ca(2+) to LAS results in the addition of Ca(2+) having a much greater impact on the self-assembly of R1/LAS and R2/LAS mixtures. For R1/LAS mixtures the addition of Ca(2+) promotes the formation of more planar structures, even at low surfactant concentrations where in the absence of Ca(2+) mixed globular micelle formation dominates. In R2/LAS mixtures, where there is a greater contrast between the high and low preferred curvatures associated with R2 and LAS, the addition of Ca(2+) results in a more complex evolution in micellar aggregation and the degree of ionization of the micelles. This results in variations in Ca(2+) binding that promotes micellar structures in which a spatial segregation of the two surfactant components within the micelle occurs.
Collapse
Affiliation(s)
- Minglei Chen
- Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Magnus Bergström L, Garamus VM. Structural behaviour of mixed cationic surfactant micelles: A small-angle neutron scattering study. J Colloid Interface Sci 2012; 381:89-99. [DOI: 10.1016/j.jcis.2012.05.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/09/2012] [Accepted: 05/10/2012] [Indexed: 11/26/2022]
|
9
|
Filippov SK, Chytil P, Konarev PV, Dyakonova M, Papadakis C, Zhigunov A, Plestil J, Stepanek P, Etrych T, Ulbrich K, Svergun DI. Macromolecular HPMA-Based Nanoparticles with Cholesterol for Solid-Tumor Targeting: Detailed Study of the Inner Structure of a Highly Efficient Drug Delivery System. Biomacromolecules 2012; 13:2594-604. [DOI: 10.1021/bm3008555] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Sergey K. Filippov
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Petr Chytil
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Petr V. Konarev
- European Molecular
Biology Laboratory, EMBL c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Margarita Dyakonova
- Physik-Department, Technische Universität München, Physik-Department,
Fachgebiet
Physik weicher Materie, James-Franck-Str. 1, 85747 Garching, Germany
| | - ChristineM. Papadakis
- Physik-Department, Technische Universität München, Physik-Department,
Fachgebiet
Physik weicher Materie, James-Franck-Str. 1, 85747 Garching, Germany
| | - Alexander Zhigunov
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Josef Plestil
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Petr Stepanek
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Tomas Etrych
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Karel Ulbrich
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Dmitri I. Svergun
- European Molecular
Biology Laboratory, EMBL c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| |
Collapse
|
10
|
Bergström LM, Garamus VM. Geometrical shape of micelles formed by cationic dimeric surfactants determined with small-angle neutron scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:9311-9321. [PMID: 22624499 DOI: 10.1021/la301190d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The influence of spacer group on the geometrical shape of micelles formed by quaternary-bis dimeric (Gemini) surfactants C(12)H(25)N(CH(3))(2)(CH(2))(s)N(CH(3))(2)C(12)H(25) (12-s-12) has been investigated with small-angle neutron scattering (SANS). Dimeric surfactants with a short spacer unit (12-3-12 and 12-4-12) are observed to form elongated general ellipsoidal micelles with half axes a < b < c, whereas SANS data demonstrate that 12-s-12 surfactants with 6 ≤ s ≤ 12 form rather small spheroidal micelles rather than strictly spherical micelles. By means of comparing our present SANS results with previously determined growth rates using time-resolved fluorescence quenching, we are able to conclude that micelles formed by 12-6-12, 12-8-12, 12-10-12, and 12-12-12 are shaped as oblate rather than prolate spheroids. As a result, our present investigation suggests a never before reported structural behavior of Gemini surfactant micelles, according to which micelles transform from elongated ellipsoids to nonelongated oblate spheroids as the length of the spacer group is increased. The aggregation number of oblate micelles is observed to monotonously decrease with an increasing length of the surfactant spacer group, mainly as a result of a decreasing minor half axis (a), whereas the major half axis (b) is rather constant with respect to s. We argue that geometrically heterogeneous elongated micelles are formed by dimeric surfactants with a short spacer group mainly as a result of the surface charges becoming less uniformly distributed over the micelle interface. As the length of the spacer group increases, the distance between intramolecular charges become approximately equal to the average distance between charges on the micelle interface, and as a result, rather small oblate spheroidal micelles with a more uniform distribution of surface charges are formed by dimeric 12-s-12 surfactants with 6 ≤ s ≤ 12.
Collapse
Affiliation(s)
- L Magnus Bergström
- School of Chemical Science and Engineering, Department of Chemistry, Surface and Corrosion Science, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | | |
Collapse
|
11
|
May A, Stébé MJ, Gutiérrez JM, Blin JL. Coexistence of two kinds of fluorinated hydrogenated micelles as building blocks for the design of bimodal mesoporous silica with two ordered mesopore networks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14000-14004. [PMID: 22043901 DOI: 10.1021/la203753q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A simple and effective route has been developed for the synthesis of bimodal (3.6 and 9.4 nm) mesoporous silica materials that have two ordered interconnected pore networks. Mesostructures have been prepared through the self-assembly mechanism by using a mixture of polyoxyethylene fluoroalkyl ether and triblock copolymer as building blocks. The investigation of the R(F)(8)(EO)(9)/P123/water phase diagram shows that in the considered surfactant range of concentrations the system is micellar (L(1)). DLS measurements indicate that this micellar phase is composed of two types of micelles; the size of the first one at around 7.6 nm corresponds unambiguously to the pure fluorinated micelles. The second type of micelles at higher diameter consists of fluorinated micelles that have accommodated a weak fraction of P123 molecules. Thus, in this study the bimodal mesoporous silica is really templated by two kinds of micelles.
Collapse
Affiliation(s)
- A May
- Chemical Engineering Department, Chemistry Faculty, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Catalonia, Spain
| | | | | | | |
Collapse
|
12
|
Almgren M, Garamus VM, Nordstierna L, Luc-Blin J, Stébé MJ. Nonideal mixed micelles of fluorinated and hydrogenous surfactants in aqueous solution. NMR and SANS studies of anionic and nonionic systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:5355-5363. [PMID: 20014778 DOI: 10.1021/la903764u] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Contrast variation SANS and (19)F chemical shifts were measured for three mixed equimolar micelle systems: sodium perfluorooctanoate (SPFO) and sodiumdecylsulfate (SDeS) in 200 mM NaCl, lithium perfluorononanate (LiPFN) and lithium dodecylsulfate (LiDS) in 200 mM LiCl, and a nonionic system C(8)F(17)C(2)H(4)(OC(2)H(4))(9) and C(12)H(25)(OC(2)H(4))(8) in water, all at 25 degrees C. The chemical shift measurements allow the calculation of the average fraction of nearest neighbors of each kind around the reporter group (the trifluoromethyl group). A preference for like neighbors were found in all systems, smallest in the SDeS/SPFO system and largest in the nonionic system, but in all cases substantially smaller than expected at critical conditions. From the SANS measurements the width of the micelle composition distribution was obtained. For the ionic systems similar values were obtained, showing a broadening compared to ideal mixtures, but not broad enough for demixing or clearly bimodal distributions. In the nonionic system the width was estimated as sigma = 0.18 and 0.22 using two different evaluation methods. These values suggest that the system is close to critical conditions. The lower value refers to a direct modeling of the system, assuming an ellipsoidal shape and a Gaussian composition distribution. The modeling showed the nonionic mixed micelles to be prolate ellipsoids with axial ratio 2.2 and an aggregation number larger than 100, whereas the two ionic systems fitted best to oblate shapes (axial ratios 0.8 and 0.65 for SDeS/SPFO and LiDS/LiPFN, respectively) and aggregation numbers of 60 for both.
Collapse
Affiliation(s)
- Mats Almgren
- Department of Physical and Analytical Chemistry, Uppsala University, Box 579 SE-751 23 Uppsala, Sweden
| | | | | | | | | |
Collapse
|
13
|
Peyre V. Segregation phenomena in micelles from mixtures of fluorinated and hydrogenated surfactants. Curr Opin Colloid Interface Sci 2009. [DOI: 10.1016/j.cocis.2009.05.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
14
|
Dong S, Xu G, Hoffmann H. Aggregation Behavior of Fluorocarbon and Hydrocarbon Cationic Surfactant Mixtures: A Study of 1H NMR and 19F NMR. J Phys Chem B 2008; 112:9371-8. [DOI: 10.1021/jp801216e] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shuli Dong
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, P. R. China, and University of Bayreuth, Bayreuth Center for Colloids and Interfaces, D-95446 Bayreuth, Germany
| | - Guiying Xu
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, P. R. China, and University of Bayreuth, Bayreuth Center for Colloids and Interfaces, D-95446 Bayreuth, Germany
| | - Heinz Hoffmann
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, P. R. China, and University of Bayreuth, Bayreuth Center for Colloids and Interfaces, D-95446 Bayreuth, Germany
| |
Collapse
|
15
|
Michaux F, Blin JL, Stébé MJ. Relation between the lower consolute boundary and the structure of mesoporous silica materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:1044-1052. [PMID: 18161998 DOI: 10.1021/la7029104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this study, we have shed some light on the relation between the position of the lower consolute boundary of various nonionic surfactants in water and the structure of the mesoporous silica materials synthesized from these surfactants-based systems. In the first part, the lower consolute boundary was shifted by adding salts. Depending on the features of the phase diagram, we have looked for either a salting out or a salting in effect. Mesoporous materials were prepared from a micellar solution of the investigated surfactants. Results clearly evidenced that the cooperative self-assembly mechanism is not favored if the lower consolute boundary is not shifted toward high temperatures. Moreover, the higher the difference between the phase separation temperature and the temperature at which the silica precursor is added to the surfactant solution, the better the mesopore ordering is. In the second part, this tendency has been confirmed by using a hydrogenated surfactant as additive.
Collapse
Affiliation(s)
- F Michaux
- Equipe Physico-chimie des Colloïdes, UMR SRSMC No. 7565, Université Henri Poincaré-Nancy 1/CNRS, Faculté des Sciences, BP 239, F-54506 Vandoeuvre-les-Nancy cedex
| | | | | |
Collapse
|
16
|
Almgren M, Garamus VM, Asakawa T, Jiang N. Contrast Variation SANS Investigation of Composition Distributions in Mixed Surfactant Micelles. J Phys Chem B 2007; 111:7133-41. [PMID: 17530797 DOI: 10.1021/jp070271x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Small angle neutron scattering measurements have been performed on three systems (HFDeP-d5-C (N-1(1,1,2,2-tetrahydroperfluorodecanoyl)pyridinium-d5 chloride)/C16PC in 63 mM NaCl; HFDeP-d5-C/C12PC in 200 mM NaCl, and as an example of an ideally mixed system, SDS/SDS-d25 in 200 mM NaCl) containing micelles formed in a binary mixture of surfactants, in order to investigate the composition distribution of the mixed micelles. The experimental data were collected varying the contrast between the average scattering length density of micelles and aqueous solvent by changing the H2O/D2O ratio. Analysis of data includes a model-independent approach--the indirect Fourier transformation method and direct modeling-simultaneous fit at all contrasts by the scattering from micelles of equal size and shape with composition distribution and an effective interaction. It has earlier been shown (Almgren, M.; Garamus, V. M. J. Phys. Chem. B 2005, 109, 11348) that for micelles of equal size, independent of the composition, and with negligible intermicellar interactions, the scattered intensity at zero angle varies quadratically with the contrast, with the minimum intensity at the nominal match point proportional to sigma2, the variance of the micelle composition distribution. Within the regular solution framework, the composition distribution and its variance are uniquely defined by the value of the interaction parameter and the micelle aggregation number. At 25 degrees C, the first system gave sigma = 0.37, corresponding to a broad, bimodal composition distribution, the second sigma = 0.22, a broad distribution with a shallow minimum at the midpoint. For SDS/SDS-d25, we found sigma = 0.006 +/- 0.030, which is a smaller value than that of the binominal composition distribution expected for an ideally mixed system.
Collapse
Affiliation(s)
- Mats Almgren
- Department of Physical and Analytical Chemistry, Uppsala University, Uppsala, Sweden.
| | | | | | | |
Collapse
|
17
|
Bergström LM. Bending Energetics of Tablet-Shaped Micelles: A Novel Approach to Rationalize Micellar Systems. Chemphyschem 2007; 8:462-72. [PMID: 17542003 DOI: 10.1002/cphc.200600692] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A novel approach to rationalize micellar systems is expounded in which the structural behavior of tablet-shaped micelles is theoretically investigated as a function of the three bending elasticity constants: spontaneous curvature (H0), bending rigidity (k(c)), and saddle-splay constant (k(c)). As a result, experimentally accessible micellar properties, such as aggregation number, length-to-width ratio, and polydispersity, may be related to the different bending elasticity constants. It is demonstrated that discrete micelles or connected cylinders form when H0 > 1/4xi, where xi is the thickness of a surfactant monolayer, whereas various bilayer structures are expected to predominate when H0 < 1/4xi. Our theory predicts, in agreement with experiments, a transition from discrete globular (tablet-shaped) micelles to a phase of ordered, or disordered, connected cylinders above a critical surfactant concentration. Moreover, a novel explanation for the mechanism of growth, from small globular to long rodlike or wormlike micelles, follows as a consequence from the theory. In accordance, polydisperse elongated micelles (large length-to-width ratio) form as the bending rigidity is lowered, approaching the critical point at k(c) = 0, whereas monodisperse globular micelles (small length-to-width ratio) are expected to be present at large k(c) values. The spontaneous curvature mainly determines the width of tablet-shaped or ribbonlike micelles, or the radius of disklike micelles, whereas the saddle-splay constant primarily influences the size but not the shape of the micelles.
Collapse
Affiliation(s)
- L Magnus Bergström
- Department of Pharmacy, Pharmaceutical Physical Chemistry, Box 580, Uppsala University, 751 23 Uppsala, Sweden.
| |
Collapse
|
18
|
Almgren M, Garamus VM. Small Angle Neutron Scattering Study of Demixing in Micellar Solutions Containing CTAC and a Partially Fluorinated Cationic Surfactant. J Phys Chem B 2005; 109:11348-53. [PMID: 16852386 DOI: 10.1021/jp0502510] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Demixing of fluorocarbon and hydrocarbon surfactants to form coexisting fluorocarbon-rich and hydrocarbon-rich micelles has been studied by small angle neutron scattering in aqueous solution, using an equimolar mixture of cetyltrimethylammonium chloride and the partially fluorinated cationic surfactant N-(1,1,2,2-tetrahydroperfluorodecanyl)pyridinium chloride, with a deuterated pyridinium headgroup. Measurements have been performed under varying experimental conditions: in both pure aqueous solutions and with salt (0.10 M NaCl), at several contrasts for neutrons obtained by varying the H(2)O/D(2)O ratio, mainly at 25 degrees C but also at 60 degrees C to promote mixing of the surfactants. The experiments show that a substantial residual scattering is retained at the solvent composition where the average scattering length density of mixed micelles would match that of the solvent. It is moreover observed that, in solutions without added salt, a prominent correlation peak observed in 100% D(2)O disappears at the match point. These observations are in accordance with a very broad composition distribution, possibly composed of two populations of mixed micelles of similar sizes but different compositions, but would not result from micelles with merely a highly inhomogeneous internal structure. Increasing the temperature from 25 to 60 degrees C reduces substantially the scattered intensity at zero angle at the match point, as expected for a less broad population of mixed micelles. In the numerical analysis, the scattering data for scattering vector q > or = 0.02 A(-1) were analyzed by the indirect Fourier transform method to give the scattering at zero angle. From these data, the average micelle aggregation number was obtained as 76 at 25 degrees C and 54 at 60 degrees C. The contrast variation results for the intensity at zero angle give a measure of the width of the micelle distribution, which is obtained as sigma = 0.33 at the lower temperature and sigma = 0.20 at 60 degrees C. The result at the low temperature is compatible with the formation of two populations that are polydisperse (sigma = 0.07) and centered around 18 and 82%; other broad distributions cannot be excluded.
Collapse
Affiliation(s)
- Mats Almgren
- Department of Physical Chemistry, Uppsala University, Box 579, SE-751 23 Uppsala, Sweden, and GKSS Research Centre, Max Planck Street, 21502 Geesthacht, Germany.
| | | |
Collapse
|
19
|
OZAWA T, ASAKAWA T, GARAMUS VM, OHTA A, MIYAGISHI S. Effect of D2O Solvent on the Micellization Behavior of 2-Hydroxy-1,1,2,3,3-pentahydroperfluoroundecyldiethyl-ammonium Halides. J Oleo Sci 2005. [DOI: 10.5650/jos.54.585] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
20
|
Pingali SV, Takiue T, Luo G, Tikhonov AM, Ikeda N, Aratono M, Schlossman ML. X-ray Reflectivity and Interfacial Tension Study of the Structure and Phase Behavior of the Interface between Water and Mixed Surfactant Solutions of CH3(CH2)19OH and CF3(CF2)7(CH2)2OH in Hexane. J Phys Chem B 2004; 109:1210-25. [PMID: 16851083 DOI: 10.1021/jp045887q] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The interface between water and mixed surfactant solutions of CH(3)(CH(2))(19)OH and CF(3)(CF(2))(7)(CH(2))(2)OH in hexane was studied with interfacial tension and X-ray reflectivity measurements. Measurements of the tension as a function of temperature for a range of total bulk surfactant concentrations and for three different values of the molal ratio of fluorinated to total surfactant concentration (0.25, 0.28, and 0.5) determined that the interface can be in three different monolayer phases. The interfacial excess entropy determined for these phases suggests that two of the phases are condensed single surfactant monolayers of CH(3)(CH(2))(19)OH and CF(3)(CF(2))(7)(CH(2))(2)OH. By studying four different compositions as a function of temperature, X-ray reflectivity was used to determine the structure of these monolayers in all three phases at the liquid-liquid interface. The X-ray reflectivity measurements were analyzed with a layer model to determine the electron density and thickness of the headgroup and tailgroup layers. The reflectivity demonstrates that phases 1 and 2 correspond to an interface fully covered by only one of the surfactants (liquid monolayer of CH(3)(CH(2))(19)OH in phase 1 and a solid condensed monolayer of CF(3)(CF(2))(7)(CH(2))(2)OH in phase 2). This was determined by analysis of the electron density profile as well as by direct comparison to reflectivity studies of the liquid-liquid interface in systems containing only one of the surfactants (plus hexane and water). The liquid monolayer of CH(3)(CH(2))(19)OH undergoes a transition to the solid monolayer of CF(3)(CF(2))(7)(CH(2))(2)OH with increasing temperature. Phase 3 and the transition regions between phases 1 and 2 consist of a mixed monolayer at the interface that contains domains of the two surfactants. In phase 3 the interface also contains gaseous regions that occupy progressively more of the interface as the temperature is increased. The reflectivity determined the coverage of the surfactant domains at the interface. A simple model is presented that predicts the basic features of the domain coverage as a function of temperature for the mixed surfactant system from the behavior of the single surfactant systems.
Collapse
|