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Anderson RL, Gunn DSD, Taddese T, Lavagnini E, Warren PB, Bray DJ. Phase Behavior of Alkyl Ethoxylate Surfactants in a Dissipative Particle Dynamics Model. J Phys Chem B 2023; 127:1674-1687. [PMID: 36786752 PMCID: PMC9969514 DOI: 10.1021/acs.jpcb.2c08834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
We present a dissipative particle dynamics (DPD) model capable of capturing the liquid state phase behavior of nonionic surfactants from the alkyl ethoxylate (CnEm) family. The model is based upon our recent work [Anderson et al. J. Chem. Phys. 2017, 147, 094503] but adopts tighter control of the molecular structure by setting the bond angles with guidance from molecular dynamics simulations. Changes to the geometry of the surfactants were shown to have little effect on the predicted micelle properties of sampled surfactants, or the water-octanol partition coefficients of small molecules, when compared to the original work. With these modifications the model is capable of reproducing the binary water-surfactant phase behavior of nine surfactants (C8E4, C8E5, C8E6, C10E4, C10E6, C10E8, C12E6, C12E8, and C12E12) with a good degree of accuracy.
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2
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Bray DJ, Anderson RL, Warren PB, Lewtas K. Modeling Alkyl Aromatic Hydrocarbons with Dissipative Particle Dynamics. J Phys Chem B 2022; 126:5351-5361. [PMID: 35797469 PMCID: PMC9310027 DOI: 10.1021/acs.jpcb.2c02048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Building on previous work studying alkanes, we develop
a dissipative
particle dynamics (DPD) model to capture the behavior of the alkyl
aromatic hydrocarbon family under ambient conditions of 298 K and
1 atmosphere. Such materials are of significant worldwide industrial
importance in applications such as solvents, chemical intermediates,
surfactants, lubricating oils, hydraulic fluids, and greases. We model
both liquids and waxy solids for molecules up to 36 carbons in size
and demonstrate that we can correctly capture both the freezing transition
and liquid-phase densities in pure substances and mixtures. We also
demonstrate the importance of including specialized bead types into
the DPD model (rather than solely relying on generic bead types) to
capture specific local geometrical constructs such as the benzene
ring found in the benzyl chemical group; this can be thought of as
representing subtle real-world many-body effects via customized pairwise
non-bonded potentials.
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Affiliation(s)
- David J Bray
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
| | - Richard L Anderson
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
| | - Patrick B Warren
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
| | - Kenneth Lewtas
- Lewtas Science & Technologies Ltd., 246 Banbury Road, Oxford OX2 7DY, United Kingdom.,School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
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Lavagnini E, Cook JL, Warren PB, Hunter CA. Systematic Parameterization of Ion-Surfactant Interactions in Dissipative Particle Dynamics Using Setschenow Coefficients. J Phys Chem B 2022; 126:2308-2315. [PMID: 35290050 PMCID: PMC9098171 DOI: 10.1021/acs.jpcb.2c00101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Dissipative
particle dynamics (DPD) simulations of nonionic surfactants
with an added salt show that the Setschenow relationship is reproduced;
that is, the critical micelle concentration is log-linearly dependent
on the added salt concentration. The simulated Setschenow coefficients
depend on the DPD bead–bead repulsion amplitudes, and matching
to the experimentally determined values provides a systematic method
to parameterize the interactions between salt ion beads and surfactant
beads. The optimized ion-specific interaction parameters appear to
be transferrable and follow the same trends as the empirical Hofmeister
series.
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Affiliation(s)
- Ennio Lavagnini
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Joanne L Cook
- Unilever R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, U.K
| | - Patrick B Warren
- Unilever R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, U.K.,STFC Hartree Centre, Sci-Tech Daresbury, Warrington WA4 4AD, U.K
| | - Christopher A Hunter
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
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Del Regno A, Warren PB, Bray DJ, Anderson RL. Critical Micelle Concentrations in Surfactant Mixtures and Blends by Simulation. J Phys Chem B 2021; 125:5983-5990. [PMID: 34043913 DOI: 10.1021/acs.jpcb.1c00893] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We explore the use of coarse-grained dissipative particle dynamics simulations to predict critical micelle concentrations (CMCs) in polydisperse surfactant mixtures and blends. By fitting pseudo-phase separation models (PSMs) to aqueous solutions of binary surfactant mixtures at selected compositions above the CMC, we avoid the need for expensive simulations of more complex multicomponent mixtures performed as a function of dilution. The approach is demonstrated for sodium laureth sulfate (SLES) surfactants with polydispersity in the ethoxylate spacer. For this system, we find a modest degree of cooperativity in micelle formation, which we attribute to the reduced repulsion between charged headgroups for surfactants with dissimilar ethoxylate spacer lengths. However, this is insufficient to explain the lowered CMC often observed in commercial SLES samples, which we attribute to the presence of small amounts of unsulfated alkyl ethoxylates and/or traces of salt.
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Affiliation(s)
- Annalaura Del Regno
- Hartree Centre, Science and Technology Facilities Council (STFC), Sci-Tech Daresbury, Warrington, WA4 4AD, U.K.,BASF SE, Materials Molecular Modeling, Carl-Bosch-Str. 38, 67056 Ludwigshafen, Germany
| | - Patrick B Warren
- Hartree Centre, Science and Technology Facilities Council (STFC), Sci-Tech Daresbury, Warrington, WA4 4AD, U.K.,Unilever R&D Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, U.K
| | - David J Bray
- Hartree Centre, Science and Technology Facilities Council (STFC), Sci-Tech Daresbury, Warrington, WA4 4AD, U.K
| | - Richard L Anderson
- Hartree Centre, Science and Technology Facilities Council (STFC), Sci-Tech Daresbury, Warrington, WA4 4AD, U.K
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Lavagnini E, Cook JL, Warren PB, Hunter CA. Translation of Chemical Structure into Dissipative Particle Dynamics Parameters for Simulation of Surfactant Self-Assembly. J Phys Chem B 2021; 125:3942-3952. [PMID: 33848165 PMCID: PMC8154614 DOI: 10.1021/acs.jpcb.1c00480] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/08/2021] [Indexed: 01/28/2023]
Abstract
Dissipative particle dynamics (DPD) can be used to simulate the self-assembly properties of surfactants in aqueous solutions, but in order to simulate a new compound, a large number of new parameters are required. New methods for the calculation of reliable DPD parameters directly from chemical structure are described, allowing the DPD approach to be applied to a much wider range of organic compounds. The parameters required to describe the bonded interactions between DPD beads were calculated from molecular mechanics structures. The parameters required to describe the nonbonded interactions were calculated from surface site interaction point (SSIP) descriptions of molecular fragments that represent individual beads. The SSIPs were obtained from molecular electrostatic potential surfaces calculated using density functional theory and used in the SSIMPLE algorithm to calculate transfer free energies between different bead liquids. This approach was used to calculate DPD parameters for a range of different types of surfactants, which include ester, amide, and sugar moieties. The parameters were used to simulate the self-assembly properties in aqueous solutions, and comparison of the results for 27 surfactants with the available experimental data shows that these DPD simulations accurately predict critical micelle concentrations, aggregation numbers, and the shapes of the supramolecular assemblies formed. The methods described here provide a general approach to determining DPD parameters for neutral organic compounds of arbitrary structure.
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Affiliation(s)
- Ennio Lavagnini
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.
K.
| | - Joanne L. Cook
- Unilever
R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, U. K.
| | - Patrick B. Warren
- Unilever
R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, U. K.
- The
Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, U. K.
| | - Christopher A. Hunter
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.
K.
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Bray DJ, Anderson RL, Warren PB, Lewtas K. Wax Formation in Linear and Branched Alkanes with Dissipative Particle Dynamics. J Chem Theory Comput 2020; 16:7109-7122. [PMID: 32857939 DOI: 10.1021/acs.jctc.0c00605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We present a dissipative particle dynamics (DPD) model for wax formation (i.e., the freezing transition) in linear and branched alkanes at room temperature (298 K) and atmospheric pressure. We parametrize the model using pure liquid phase densities and the onset of wax formation as a function of alkyl chain length. Significant emphasis is placed on building an accurate representation of the underlying molecular architecture by careful consideration of bond lengths and angles, aided by distributions obtained from molecular dynamics simulation. Using the derived model, we observe wax formation in n-alkanes when the alkyl chain length is greater than 18 (n-octadecane), in excellent agreement with experimental observations. Further, we reproduce the behavior of branched alkanes and mixtures including solubilities of heavy alkanes in light alkane solvents.
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Affiliation(s)
- David J Bray
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
| | - Richard L Anderson
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
| | - Patrick B Warren
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom.,Unilever R&D Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, United Kingdom
| | - Kenneth Lewtas
- Lewtas Science & Technologies Ltd., 246 Banbury Road, Oxford OX2 7DY, United Kingdom.,School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
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Johnston MA, Duff AI, Anderson RL, Swope WC. Model for the Simulation of the C nE m Nonionic Surfactant Family Derived from Recent Experimental Results. J Phys Chem B 2020; 124:9701-9721. [PMID: 32986421 DOI: 10.1021/acs.jpcb.0c06132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using a comprehensive set of recently published experimental results for training and validation, we have developed computational models appropriate for simulations of aqueous solutions of poly(ethylene oxide) alkyl ethers, an important class of micelle-forming nonionic surfactants, usually denoted CnEm. These models are suitable for use in simulations that employ a moderate amount of coarse graining and especially for dissipative particle dynamics (DPD), which we adopt in this work. The experimental data used for training and validation were reported earlier and produced in our laboratory using dynamic light scattering (DLS) measurements performed on 12 members of the CnEm compound family yielding micelle size distribution functions and mass-weighted mean aggregation numbers at each of several surfactant concentrations. The range of compounds and quality of the experimental results were designed to support the development of computational models. An essential feature of this work is that all simulation results were analyzed in a way that is consistent with the experimental data. Proper account is taken of the fact that a broad distribution of micelle sizes exists, so mass-weighted averages (rather than number-weighted averages) over this distribution are required for the proper comparison of simulation and experimental results. The resulting DPD force field reproduces several important trends seen in the experimental critical micelle concentrations and mass-averaged mean aggregation numbers with respect to surfactant characteristics and concentration. We feel it can be used to investigate a number of open questions regarding micelle sizes and shapes and their dependence on surfactant concentration for this important class of nonionic surfactants.
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Affiliation(s)
| | - Andrew Ian Duff
- STFC Hartree Centre, SciTech Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - Richard L Anderson
- STFC Hartree Centre, SciTech Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - William C Swope
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, United States
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Wand CR, Panoukidou M, Del Regno A, Anderson RL, Carbone P. The Relationship between Wormlike Micelle Scission Free Energy and Micellar Composition: The Case of Sodium Lauryl Ether Sulfate and Cocamidopropyl Betaine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12288-12298. [PMID: 32988195 DOI: 10.1021/acs.langmuir.0c02210] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The scission energy is the difference in free energy between two hemispherical caps and the cylindrical region of a wormlike micelle. This energy difference determines the logarithm of the average micelle length, which affects several macroscopic properties such as the viscosity of viscoelastic fluids. Here we use a recently published method by Wang et al. ( Langmuir, 2018, 34, 1564-1573) to directly calculate the scission energy of micelles composed of monodisperse sodium lauryl ether sulfate (SLESnEO), an anionic surfactant. Utilizing dissipative particle dynamics (DPD), we perform a systematic study varying the number of ethoxyl groups (n) and salt concentration. The scission energy increases with increasing salt concentration, indicating that the formation of longer micelles is favored. We attribute this to the increased charge screening that reduces the repulsion between head groups. However, the scission energy decreases with increasing number of ethoxyl groups as the flexibility of the head group increases and the sodium ion becomes less tightly bound to the head group. We then extend the analysis to look at the effect of a common cosurfactant, cocamidopropyl betaine (CAPB), and find that its addition stabilizes wormlike micelles at a lower salt concentration.
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Affiliation(s)
- Charlie R Wand
- Department of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Maria Panoukidou
- Department of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Annalaura Del Regno
- STFC Hartree Centre, Sci-Tech Daresbury, Warrington WA4 4AD, United Kingdom
- Materials Molecular Modeling, BASF SE, Carl Bosch Strasse 38, 67056, Ludwigshafen, Germany
| | - Richard L Anderson
- STFC Hartree Centre, Sci-Tech Daresbury, Warrington WA4 4AD, United Kingdom
| | - Paola Carbone
- Department of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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10
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Conchuir BO, Gardner K, Jordan KE, Bray DJ, Anderson RL, Johnston MA, Swope WC, Harrison A, Sheehy DR, Peters TJ. Efficient Algorithm for the Topological Characterization of Worm-like and Branched Micelle Structures from Simulations. J Chem Theory Comput 2020; 16:4588-4598. [DOI: 10.1021/acs.jctc.0c00311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - Kirk Gardner
- Department of Computer Science & Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Kirk E. Jordan
- IBM T. J. Watson Research, Cambridge, Massachusetts 02142, United States
| | - David J. Bray
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, U.K
| | | | | | - William C. Swope
- IBM Almaden Research Center, San Jose, California 95120, United States
| | - Alex Harrison
- IBM Research Europe, The Hartree Centre, Daresbury WA4 4AD, U.K
| | - Donald R. Sheehy
- Department of Computer Science, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Thomas J. Peters
- Department of Computer Science & Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
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11
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Constructing the phase diagram of sodium laurylethoxysulfate using dissipative particle dynamics. J Colloid Interface Sci 2019; 557:34-44. [DOI: 10.1016/j.jcis.2019.08.091] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/23/2019] [Accepted: 08/24/2019] [Indexed: 01/08/2023]
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