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Hussain M, Nagaraj M, Cayre OJ, Robles ESJ, Tantawy H, Bayly AE. Aqueous Phase Behavior of a NaLAS-Polycarboxylate Polymer System. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5099-5108. [PMID: 33877849 DOI: 10.1021/acs.langmuir.0c03280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Linear alkylbenzene sulfonate (NaLAS) surfactant is often combined with polycarboxylate polymers in detergent formulations. However, the behavior of these aqueous surfactant-polymer systems in the absence of an added electrolyte is unreported. This work investigates the behavior of such systems using polarized light microscopy, small-angle X-ray scattering (SAXS), centrifugation, and 2H NMR techniques. A phase diagram at 50 °C is reported for 0-50 wt % NaLAS concentrations and 0-10 wt % polycarboxylate concentrations. The NaLAS-water system is micellar at concentrations <35 wt %, and a 2-phase micellar-lamellar system is seen at higher NaLAS levels, consistent with that reported by previous studies. As polymers are added at low surfactant concentrations (∼10 to 20 wt % NaLAS), a second optically isotropic phase is formed; this is thought to be a polymer-rich phase. Further addition of polycarboxylate leads to the formation of a lamellar phase. At high surfactant concentrations (>20 wt % NaLAS), the addition of a polymer induces a second lamellar phase. These observed behaviors are thought to arise as a result of depletion flocculation and salting-out effects. The observed lamellar phases adopt colloidal multilamellar vesicle (MLV) structures, and the average MLV radii were estimated using 2H NMR by probing the diffusion and anisotropy of D2O within the bilayers of the vesicles. The NMR results show that as the polymer concentration was increased from 0 to 10 wt %, an increase in the average multilamellar vesicle size from ∼200 to ∼500 nm was observed. This increase in the calculated average MLV radius likely results from depletion flocculation-induced MLV fusion.
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Affiliation(s)
- Mariam Hussain
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Mamatha Nagaraj
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Olivier J Cayre
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Eric S J Robles
- The Procter and Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
| | - Hossam Tantawy
- The Procter and Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
| | - Andrew E Bayly
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
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Rafique AS, Khodaparast S, Poulos AS, Sharratt WN, Robles ESJ, Cabral JT. Micellar structure and transformations in sodium alkylbenzenesulfonate (NaLAS) aqueous solutions: effects of concentration, temperature, and salt. SOFT MATTER 2020; 16:7835-7844. [PMID: 32756697 DOI: 10.1039/d0sm00982b] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigate the shape, dimensions, and transformation pathways of micelles of linear sodium alkylbenzenesulfonate (NaLAS), a common anionic surfactant, in aqueous solution. Employing Small Angle Neutron Scattering (SANS) and surface tensiometry, we quantify the effects of surfactant concentration (0.6-15 wt%), temperature (5-40 °C) and added salt (≤0.35 M Na2SO4). Spherical micelles form at low NaLAS (≤2.6 wt%) concentration in water, and become elongated with increasing concentration and decreasing temperature. Addition of salt reduces the critical micelle concentration (CMC) and thus promotes the formation of micelles. At fixed NaLAS concentration, salt addition causes spherical micelles to grow into cylindrical micelles, and then multilamellar vesicles (MLVs), which we examine by SANS and cryo-TEM. Above a threshold salt concentration, the MLVs reach diameters of 100 s of nm to few μm, eventually causing precipitation. While the salt concentrations associated with the micelle-to-cylinder transformation increase only slightly with temperature, those required for the cylinder-to-MLV transformation exhibit a pronounced, linear temperature dependence, which we examine in detail. Our study establishes a solution structure map for this model anionic surfactant in water, quantifying the combined roles of concentration, temperature and salt, at practically relevant conditions.
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Affiliation(s)
- Aysha S Rafique
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Sepideh Khodaparast
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Andreas S Poulos
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - William N Sharratt
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Eric S J Robles
- The Procter & Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne, NE12 9TS, UK
| | - João T Cabral
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
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Baez-Cotto CM, Mahanthappa MK. Micellar Mimicry of Intermetallic C14 and C15 Laves Phases by Aqueous Lyotropic Self-Assembly. ACS NANO 2018; 12:3226-3234. [PMID: 29611426 DOI: 10.1021/acsnano.7b07475] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Concentration-dependent supramolecular self-assembly of amphiphilic molecules in water furnishes a variety of nanostructured lyotropic liquid crystals (LLCs), which typically display high symmetry bicontinuous network and discontinuous micellar morphologies. Aqueous dispersions of soft spherical micelles derived from small molecule amphiphile hydration typically pack into exemplary body-centered cubic and closest-packed LLCs. However, investigations of hydrated mixtures of the ionic surfactant tetramethylammonium decanoate loaded with 40 wt % n-decane (TMADec-40) revealed the formation of a high symmetry bicontinuous double diamond LLC, as well as cubic C15 and hexagonal C14 Laves LLC phases that mirror the MgCu2 and MgZn2 intermetallic structure types, respectively. Detailed small-angle X-ray scattering analyses demonstrate that the complex C15 and C14 LLCs exhibit large unit cells, in which 12 or more ∼3-4 nm diameter micelles of multiple discrete sizes arrange into tetrahedral close packing arrangements with exceptional long-range translational order. The symmetry breaking that drives self-assembly into these low-symmetry LLC phases is rationalized in terms of a frustrated balance between maximizing counterion-mediated micellar cohesion within the ensemble of oil-swollen particles, while simultaneously optimizing local spherical particle symmetry to minimize molecular-level variations in surfactant solvation.
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Affiliation(s)
- Carlos M Baez-Cotto
- Department of Chemistry , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , United States
| | - Mahesh K Mahanthappa
- Department of Chemistry , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , United States
- Department of Chemical Engineering and Materials Science , University of Minnesota , 421 Washington Ave. SE , Minneapolis , Minnesota 55455 , United States
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Insights into the Dissolution Kinetics of NaLAS Tablets. J SURFACTANTS DETERG 2017. [DOI: 10.1007/s11743-017-2017-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zimbitas G, Fryer PJ, Zhang Z, Bakalis S. Free-standing thin film interactions with small particles. INNOV FOOD SCI EMERG 2017. [DOI: 10.1016/j.ifset.2016.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Poulos AS, Nania M, Lapham P, Miller RM, Smith AJ, Tantawy H, Caragay J, Gummel J, Ces O, Robles ESJ, Cabral JT. Microfluidic SAXS Study of Lamellar and Multilamellar Vesicle Phases of Linear Sodium Alkylbenzenesulfonate Surfactant with Intrinsic Isomeric Distribution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5852-5861. [PMID: 27196820 DOI: 10.1021/acs.langmuir.6b01240] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The structure and flow behavior of a concentrated aqueous solution (45 wt %) of the ubiquitous linear sodium alkylbenzenesulfonate (NaLAS) surfactant is investigated by microfluidic small-angle X-ray scattering (SAXS) at 70 °C. NaLAS is an intrinsically complex mixture of over 20 surfactant molecules, presenting coexisting micellar (L1) and lamellar (Lα) phases. Novel microfluidic devices were fabricated to ensure pressure and thermal resistance, ability to handle viscous fluids, and low SAXS background. Polarized light optical microscopy showed that the NaLAS solution exhibits wall slip in microchannels, with velocity profiles approaching plug flow. Microfluidic SAXS demonstrated the structural spatial heterogeneity of the system with a characteristic length scale of 50 nL. Using a statistical flow-SAXS analysis, we identified the micellar phase and multiple coexisting lamellar phases with a continuous distribution of d spacings between 37.5 and 39.5 Å. Additionally, we showed that the orientation of NaLAS lamellar phases is strongly affected by a single microfluidic constriction. The bilayers align parallel to the velocity field upon entering a constriction and perpendicular to it upon exiting. On the other hand, multilamellar vesicle phases are not affected under the same flow conditions. Our results demonstrate that despite the compositional complexity inherent to NaLAS, microfluidic SAXS can rigorously elucidate its structure and flow response.
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Affiliation(s)
| | | | - Paul Lapham
- The Procter & Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
| | | | - Andrew J Smith
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0QX, United Kingdom
| | - Hossam Tantawy
- The Procter & Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
| | - Joel Caragay
- The Procter & Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
| | - Jérémie Gummel
- The Procter & Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
| | | | - Eric S J Robles
- The Procter & Gamble Company, Newcastle Innovation Centre, Newcastle-Upon-Tyne NE12 9TS, United Kingdom
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Li H, Dang L, Yang S, Li J, Wei H. The study of phase behavior and rheological properties of lyotropic liquid crystals in the LAS/AES/H2O system. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.01.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Liu Y, Dang L, Tan H, Wei H. Phase Behavior of Commercial AES/Ethanol/H2O Ternary System. J DISPER SCI TECHNOL 2015. [DOI: 10.1080/01932691.2015.1027910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Perroni DV, Baez-Cotto CM, Sorenson GP, Mahanthappa MK. Linker Length-Dependent Control of Gemini Surfactant Aqueous Lyotropic Gyroid Phase Stability. J Phys Chem Lett 2015; 6:993-998. [PMID: 26262858 DOI: 10.1021/acs.jpclett.5b00092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Network-phase lyotropic liquid crystals (LLCs) derived from the water-directed self-assembly of small molecule amphiphiles comprise a useful class of soft nanomaterials, with wide-ranging applications in structural biology and membrane science. However, few known surfactants enable access to these mesophases over wide temperature and amphiphile concentration phase windows. Recent studies have demonstrated that gemini ("twin tail") dicarboxylate surfactants, in which alkyl carboxylates are covalently linked near the headgroups by a hydrophobic bridge, exhibit increased propensities to form double gyroid network phase LLCs. We demonstrate herein that the lyotropic self-assembly behaviors of gemini dicarboxylates sensitively depend on the linker length, whereby odd-carbon linkers stabilize the double gyroid network LLC over unprecedented amphiphile concentration windows up to ∼45 wt % wide between T ≈ 22-80 °C. These self-assembly phenomena, which arise from the linker length-dependent preferred molecular conformations of these amphiphiles, will broaden the technological applications of these nanostructured LLCs.
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Affiliation(s)
- Dominic V Perroni
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Carlos M Baez-Cotto
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Gregory P Sorenson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Mahesh K Mahanthappa
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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