1
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Silva GMC, Morgado P, Filipe EJM. Towards compartmentalized micelles: Mixed perfluorinated and hydrogenated ionic surfactants in aqueous solution. J Colloid Interface Sci 2024; 654:906-914. [PMID: 37898074 DOI: 10.1016/j.jcis.2023.10.100] [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: 07/19/2023] [Revised: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 10/30/2023]
Abstract
HYPOTHESIS Aqueous solutions of mixtures of hydrogenated and perfluorinated ionic surfactants are known to display anomalous aggregation behavior due to the mutual phobicity between hydrogenated and perfluorinated chains. Despite all efforts, different experimental limitations prevented so far a definite interpretation of the existing experimental results: both intermicellar and intramicellar segregation remain acceptable possibilities. METHOD The potential for segregation of mixtures of fluorinated and hydrogenated ionic surfactants in water was assessed using atomistic molecular dynamics simulations. Aqueous mixtures of hydrogenated and perfluorinated ionic surfactants were studied: mixtures of anionic surfactants (sodium dodecylsulfate (SDS) + sodium perfluoro-octanoate (SPFO)) and catanionic surfactants (decyltrimethylammonium bromide (DeTAB) + SPFO) were simulated. FINDINGS The mixture of anionic surfactants, SDS + SPFO, exhibits clear intramicellar segregation between fluorinated and hydrogenated chains, displaying hydrogenous-rich and fluorous-rich regions. Compartmentalized micelles are thus clearly formed. The simulation results also suggest the possibility of intermicellar segregation. Conversely, catanionic mixtures of DeTAB and SPFO in water solution assemble into a large oblate structure, containing all available molecules in the simulation box, resembling a double layer membrane or a vesicle wall. In this case mixing between fluorinated and hydrogenated surfactants is dictated by charge alternation.
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Affiliation(s)
- Gonçalo M C Silva
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Departamento de Engenharia Química, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| | - Pedro Morgado
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Departamento de Engenharia Química, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| | - Eduardo J M Filipe
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Departamento de Engenharia Química, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
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2
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Kehrein J, Gürsöz E, Davies M, Luxenhofer R, Bunker A. Unravel the Tangle: Atomistic Insight into Ultrahigh Curcumin-Loaded Polymer Micelles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303066. [PMID: 37403298 DOI: 10.1002/smll.202303066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/22/2023] [Indexed: 07/06/2023]
Abstract
Amphiphilic ABA-triblock copolymers, comprised of poly(2-oxazoline) and poly(2-oxazine), can solubilize poorly water-soluble molecules in a structure-dependent manner forming micelles with exceptionally high drug loading. All-atom molecular dynamics simulations are conducted on previously experimentally characterized, curcumin-loaded micelles to dissect the structure-property relationships. Polymer-drug interactions for different levels of drug loading and variation in polymer structures of both the inner hydrophobic core and outer hydrophilic shell are investigated. In silico, the system with the highest experimental loading capacity shows the highest number of drug molecules encapsulated by the core. Furthermore, in systems with lower loading capacity outer A blocks show a greater extent of entanglement with the inner B blocks. Hydrogen bond analyses corroborate previous hypotheses: poly(2-butyl-2-oxazoline) B blocks, found experimentally to have reduced loading capacity for curcumin compared to poly(2-propyl-2-oxazine), establish fewer but longer-lasting hydrogen bonds. This possibly results from different sidechain conformations around the hydrophobic cargo, which is investigated by unsupervised machine learning to cluster monomers in smaller model systems mimicking different micelle compartments. Exchanging poly(2-methyl-2-oxazoline) with poly(2-ethyl-2-oxazoline) leads to increased drug interactions and reduced corona hydration; this suggests an impairment of micelle solubility or colloidal stability. These observations can help driving forward a more rational a priori nanoformulation design.
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Affiliation(s)
- Josef Kehrein
- Soft Matter Chemistry, Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki, 00014, Finland
- Division of Pharmaceutical Biosciences, Drug Research Program, Faculty of Pharmacy, University of Helsinki, Helsinki, 00014, Finland
| | - Ekinsu Gürsöz
- Soft Matter Chemistry, Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki, 00014, Finland
- Division of Pharmaceutical Biosciences, Drug Research Program, Faculty of Pharmacy, University of Helsinki, Helsinki, 00014, Finland
| | - Matthew Davies
- Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Robert Luxenhofer
- Soft Matter Chemistry, Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki, 00014, Finland
| | - Alex Bunker
- Division of Pharmaceutical Biosciences, Drug Research Program, Faculty of Pharmacy, University of Helsinki, Helsinki, 00014, Finland
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3
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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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4
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Farafonov VS, Lebed AV, Nerukh DA, Mchedlov-Petrossyan NO. Estimation of Nanoparticle's Surface Electrostatic Potential in Solution Using Acid-Base Molecular Probes II: Insight from Atomistic Simulations of Micelles. J Phys Chem B 2023; 127:1031-1038. [PMID: 36657036 DOI: 10.1021/acs.jpcb.2c07028] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Exploiting acid-base indicators as molecular probes is one of the most popular methods for determining the surface electrostatic potential Ψ in hydrophilic colloids like micellar surfactant solutions and related systems. Specifically, the indicator's apparent acidity constant index is measured in the colloid solution of interest and, as a rule, in a nonionic surfactant solution; the difference between the two is proportional to Ψ. Despite the widespread use of this approach, a major problem remains unresolved, namely, the dissimilarity of Ψ values obtained with different indicators for the same system. The common point of view recognizes the effect of several factors (the choice of the nonionic surfactant, the probe's localization, and the degree of hydration of micellar pseudophase) but does not allow to quantitatively assess their impact and decide which indicator reports the most correct Ψ value. Here, based on the ability to predict the reported Ψ values in silico, we examined the role of these factors using molecular dynamics simulations for five probes and two surfactants. The probe's hydration in the Stern layer was found responsible for approximately half of the dissimilarity range. The probe's localization is found important but hard to quantify because of the irregular structure of the Stern layer. The most accurate indicators among the examined set were identified. Supplementing experiments on measuring Ψ with molecular dynamics simulation is proposed as a way of improving the efficacy of the indicator method: the simulations can guide the choice of the most suitable probe and nonionic surfactant for the given nanoparticles.
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Affiliation(s)
- Vladimir S Farafonov
- Department of Physical Chemistry, V. N. Karazin National University, Kharkiv61022, Ukraine.,Department of Mathematics, Aston University, BirminghamB4 7ET, U.K
| | - Alexander V Lebed
- Department of Physical Chemistry, V. N. Karazin National University, Kharkiv61022, Ukraine
| | - Dmitry A Nerukh
- Department of Mathematics, Aston University, BirminghamB4 7ET, U.K
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5
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Jarin Z, Agolini O, Pastor RW. Finite-Size Effects in Simulations of Peptide/Lipid Assembly. J Membr Biol 2022; 255:437-449. [PMID: 35854128 PMCID: PMC9581812 DOI: 10.1007/s00232-022-00255-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/17/2022] [Indexed: 11/29/2022]
Abstract
Abstract Molecular dynamics simulations are an attractive tool for understanding lipid/peptide self-assembly but can be plagued by inaccuracies when the system sizes are too small. The general guidance from self-assembly simulations of homogeneous micelles is that the total number of surfactants should be three to five times greater than the equilibrium aggregate number of surfactants per micelle. Herein, the heuristic is tested on the more complicated self-assembly of lipids and amphipathic peptides using the Cooke and Martini 3 coarse-grained models. Cooke model simulations with 50 to 1000 lipids and no peptide are dominated by finite-size effects, with usually one aggregate (micelle or nanodisc) containing most of the lipids forming at each system size. Approximately 200 systems of different peptide/lipid (P/L) ratios and sizes of up to 1000 lipids yield a “finite-size phase diagram” for peptide driven self-assembly, including a coexistence region of micelles and discs. Insights from the Cooke model are applied to the assembly of dimyristoylphosphatidylcholine and the ELK-neutral peptide using the Martini 3 model. Systems of 150, 450, and 900 lipids with P/L = 1/6.25 form mixtures of lipid-rich discs that agree in size with experiment and peptide-rich micelles. Only the 150-lipid system shows finite-size effects, which arise from the long-tailed distribution of aggregate sizes. The general rule of three to five times the equilibrium aggregate size remains a practical heuristic for the Cooke and Martini 3 systems investigated here. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s00232-022-00255-9.
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Affiliation(s)
- Zack Jarin
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Olivia Agolini
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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6
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Peroukidis SD, Stott IP, Mavrantzas VG. Coarse-Grained Model Incorporating Short- and Long-Range Effective Potentials for the Fast Simulation of Micelle Formation in Solutions of Ionic Surfactants. J Phys Chem B 2022; 126:5555-5569. [PMID: 35838193 DOI: 10.1021/acs.jpcb.2c02751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A coarse-grained model comprising short- and long-range effective potentials, parametrized with the iterative Boltzmann inversion (IBI) method, is presented for capturing micelle formation in aqueous solutions of ionic surfactants using as a model system sodium dodecyl sulfate (SDS). In the coarse-grained (CG) model, each SDS molecule is represented as a sequence of four beads while each water molecule is modeled as a single bead. The proposed CG scheme involves ten potential energy functions: four of them describe bonded interactions and control the distribution functions of intramolecular degrees of freedom (bond lengths, valence angles, and dihedrals) along an SDS molecule while the other six account for intermolecular interactions between pairs of SDS and water beads and control the radial distribution functions. The nonbonded effective potentials between coarse-grained SDS molecules extend up to about 12 nm and capture structural and morphological features of the micellar solution both at short and long distances. The long-range component of these potentials, in particular, captures correlations between surfactant molecules belonging to different micelles and is essential to describe ordering associated with micelle formation. A new strategy is introduced for determining the effective potentials through IBI by using information (target distribution functions) extracted from independent atomistic simulations of a micellar reference system (a salt-free SDS solution at total surfactant concentration cT equal to 103 mM, temperature T equal to 300 K, and pressure P equal to 1 atm) obtained through a multiscale approach described in an earlier study. It employs several optimization steps for bonded and nonbonded interactions and a gradual parametrization of the short- and long-range components of the latter, followed by reparametrization of the bonded ones. The proposed CG model can reproduce remarkably accurately the microstructure and morphology of the reference system within only a few hours of computational time. It is therefore very promising for future studies of structural and morphological behavior of various liquid surfactant formulations.
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Affiliation(s)
- Stavros D Peroukidis
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504, Patras, Greece
| | - Ian P Stott
- Unilever Research and Development Port Sunlight, Bebington CH63 3JW, United Kingdom
| | - Vlasis G Mavrantzas
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504, Patras, Greece.,Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland
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7
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Critical micelle concentration of SDS through DPD simulations using COSMO-RS–based interaction parameters, the thermal effects. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Mesoscale Modeling of Agglomeration of Molecular Bottlebrushes: Focus on Conformations and Clustering Criteria. Polymers (Basel) 2022; 14:polym14122339. [PMID: 35745920 PMCID: PMC9227207 DOI: 10.3390/polym14122339] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 02/04/2023] Open
Abstract
Using dissipative particle dynamics, we characterize dynamics of aggregation of molecular bottlebrushes in solvents of various qualities by tracking the number of clusters, the size of the largest cluster, and an average aggregation number. We focus on a low volume fraction of bottlebrushes in a range of solvents and probe three different cutoff criteria to identify bottlebrushes belonging to the same cluster. We demonstrate that the cutoff criteria which depend on both the coordination number and the length of the side chain allows one to correlate the agglomeration status with the structural characteristics of bottlebrushes in solvents of various qualities. We characterize conformational changes of the bottlebrush within the agglomerates with respect to those of an isolated bottlebrush in the same solvents. The characterization of bottlebrush conformations within the agglomerates is an important step in understanding the relationship between the bottlebrush architecture and material properties. An analysis of three distinct cutoff criteria to identify bottlebrushes belonging to the same cluster introduces a framework to identify both short-lived transient and long-lived agglomerates; the same approach could be further extended to characterize agglomerates of various macromolecules with complex architectures beyond the specific bottlebrush architecture considered herein.
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9
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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
![]()
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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10
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Chen IC, Lee MT. Rhamnolipid Biosurfactants for Oil Recovery: Salt Effects on the Structural Properties Investigated by Mesoscale Simulations. ACS OMEGA 2022; 7:6223-6237. [PMID: 35224385 PMCID: PMC8867548 DOI: 10.1021/acsomega.1c06741] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Rhamnolipids (RLs) are biosurfactants produced by Pseudomonas. The biodegradability and the variety of their functionality make them suitable for environmental remediation and oil recovery. We use dissipative particle dynamics simulations to investigate the aggregation behaviors of ionic RL congeners with nonane in various operating conditions. Under zero-salinity conditions, all RL congeners studied here form small ellipsoidal clusters with detectable free surfactants. When salt ions are present, the electrostatic repulsion between the ionized heads is overcome, resulting in the formation of larger aggregates of unique structures. RLs with C10-alkyl tails tend to form elongated wormlike micelles, while RLs with C16-alkyl tails tend to form clusters in spherical symmetry, including vesicles. Di-rhamnolipids (dRLs) require stronger solvation than monorhamnolipids (mRLs) to form clusters, and the resulting size of micelles is decreased. The morphology of the mixed dRL/mRL/oil systems is controlled based on the type of the congeners and the oil contents. In addition, the divalent calcium ions are found to be influential to the structure of the micelles through different mechanisms. For 5 wt % salinity, the ionic RLs can form oil-swollen micelles up to a 1:1 surfactant-to-oil ratio, suggesting that ionic RLs are superb to act as cleaning agents for petroleum hydrocarbons in the marine area. These key findings may guide the design for RL-based washing techniques in enhanced oil recovery.
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11
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Zhang X, Kindt JT. Free energy of micellization of dodecyl phosphocholine (DPC) from molecular simulation: Hybrid PEACH-BAR method. J Comput Chem 2021; 42:2221-2232. [PMID: 34561897 DOI: 10.1002/jcc.26751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 07/08/2021] [Accepted: 09/05/2021] [Indexed: 11/06/2022]
Abstract
A new method to extract the free energy of aggregation versus aggregate size from molecular simulation data is proposed and applied to a united atom model of the zwitterionic surfactant dodecyl phosphocholine in water. This system's slow dissociation rate and low critical micelle concentration (CMC of approximately 1-2 mM) make extraction of cluster free energies directly from simulation results using the "partition-enabled analysis of cluster histogram" (PEACH) method impractical. The new approach applies PEACH to a model with weakened attractions between aggregants, which allows sampling of a continuous range of cluster sizes, then recovers the free energy of aggregation under the original fully-attractive force field using the BAR free energy difference method. PEACH-BAR results are compared with free energy differences calculated via umbrella sampling, and are used to make predictions of CMC, average cluster size, and SAXS scattering profiles that are in fair agreement with experiment.
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Affiliation(s)
- Xiaokun Zhang
- Department of Chemistry, Emory University, Atlanta, Georgia, USA
| | - James T Kindt
- Department of Chemistry, Emory University, Atlanta, Georgia, USA
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12
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Lee MT. Micellization of Rhamnolipid Biosurfactants and Their Applications in Oil Recovery: Insights from Mesoscale Simulations. J Phys Chem B 2021; 125:9895-9909. [PMID: 34423979 DOI: 10.1021/acs.jpcb.1c05802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The dissipative particle dynamics (DPD) mesoscopic method is used to investigate the self-assembly of rhamnolipid congeners and their aggregation behaviors with paraffins including nonane and pentadecane. The coarse-grained force field is parameterized by combining molecular dynamics (MD) simulations, COSMOtherm calculations, and available experimental data. This model reproduces the vesicular formation of α-l-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoate (Rha-C10-C10) reported by all-atom MD simulations. The vesicle composed of Rha-C10-C10 is found to be most stable at a surfactant concentration of 100-146 mM based on asphericity analysis. The architecture of rhamnolipid congeners affects the morphology of their aggregates. Di-rhamno-di-lipidic dRha-C16-C16 forms vesicles with a thicker unilamellar layer of 3.2 nm. Rha-C16-C16 forms vesicles at a lower concentration of 70 mM, but the enclosed water space collapses when the surfactant concentration increases. dRha-C10-C10 forms wormlike micelles, which agglomerate into a torus and interconnected network at higher concentrations. In the presence of alkane molecules, dRha-C10-C10 maintains its wormlike micellar morphology with alkane molecules wrapped inside the aggregates. For Rha-C10-C10, Rha-C16-C16, and dRha-C16-C16, nonane molecules are distributed in the hydrophobic subdomain formed by rhamnolipid molecules. Spherical vesicles are formed at a surfactant concentration of 50 mM and then develop into ellipsoidal vesicles when the concentration increases to 125 mM. When mixed with pentadecane, the alkane molecules are aggregated and surrounded by surfactants forming a core-shell structure at a low surfactant concentration of 20 mM. At higher alkane and surfactant concentrations, the morphologies develop into disk micelles, wormlike micelles, and vesicles, with pentadecane molecules being distributed and packed with rhamnolipids. The obtained simulation results suggest that these biosurfactants have potential as environmental remediation agents.
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Affiliation(s)
- Ming-Tsung Lee
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 10608, Taiwan
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13
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van der Haven DLH, Köhler S, Schreiner E, In 't Veld PJ. Closed-Form Coexistence Equation for Phase Separation of Polymeric Mixtures in Dissipative Particle Dynamics. J Phys Chem B 2021; 125:7485-7498. [PMID: 34196184 DOI: 10.1021/acs.jpcb.0c11274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To date, no extensive study of the phase diagram for binary fluid mixtures in dissipative particle dynamics (DPD) has been published. This is especially pertinent for newer parameterization schemes where the self-self interaction, or the effective volume, of different particle types is varied. This work presents an exhaustive study of the parameter space concerning DPD particles with soft interaction potentials. Moreover, we propose a closed-form coexistence equation or binodal curve that is inspired by the Flory-Huggins model. This equation describes the phase diagram of all binary mixtures made up out of monomers, homopolymers, and the mixtures thereof when self-self interactions are varied. The mean absolute percentage error (MAPE) of the equation on simulated data, including validation simulations, is 1.02%. The equation can a priori predict the phase separation of mixtures using only DPD interaction parameters. The proposed coexistence equation can therefore be used to directly validate interaction parameters resulting from novel parameterization schemes, including coarse graining and equations of state, without the need for additional simulations. Finally, it is shown that the choice of bond potential markedly influences phase behavior.
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Affiliation(s)
- Dingeman L H van der Haven
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
| | - Stephan Köhler
- Polymer Physics, BASF SE, Ludwigshafen am Rhein 67056, Germany
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14
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Zheng M, Charbonneau P. Characterization and efficient Monte Carlo sampling of disordered microphases. J Chem Phys 2021; 154:244506. [DOI: 10.1063/5.0052114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- Mingyuan Zheng
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Patrick Charbonneau
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
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15
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Harris JJ, Pantelopulos GA, Straub JE. Finite-Size Effects and Optimal System Sizes in Simulations of Surfactant Micelle Self-Assembly. J Phys Chem B 2021; 125:5068-5077. [PMID: 33961427 DOI: 10.1021/acs.jpcb.1c01186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The spontaneous formation of micelles in aqueous solutions is governed by the amphipathic nature of surfactants and is practically interesting due to the regular use of micelles as membrane mimics, for the characterization of protein structure, and for drug design and delivery. We performed a systematic characterization of the finite-size effect observed in single-component dodecylphosphocholine (DPC) micelles with the coarse-grained MARTINI model. Of multiple coarse-grained solvent models investigated using large system sizes, the nonpolarizable solvent model was found to most accurately reproduce SANS spectra of 100 mM DPC in aqueous solution. We systematically investigated the finite-size effect at constant 100 mM concentration in 23 systems of sizes 40-150 DPC, confirming the finite-size effect to manifest as an oscillation in the mean micelle aggregation number about the thermodynamic aggregation number as the system size increases. The oscillations in aggregation number mostly diminish once the system supports the formation of three micelles. Similar oscillations were observed in the estimated critical micelle concentration with a mean value of 1.10 mM, which is in agreement with experiment to 0.1 mM. The accuracy of using a multiscale simulation approach to avoid finite-size effects in the micelle size distribution and SANS spectra using MARTINI and CHARMM36 was explored using multiple long time scale 500 DPC coarse-grained simulations, which were back-mapped to CHARMM36 all-atom systems. It was found that the MARTINI model generally occupies more volume than the all-atom model, leading to the formation of micelles that are of a reasonable radius of gyration but are smaller in aggregation number. The systematic characterization of the finite-size effect and exploration of multiscale modeling presented in this work provide guidance for the accurate modeling of micelles in simulations.
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Affiliation(s)
- Jonathan J Harris
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - George A Pantelopulos
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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16
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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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17
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Lai C, Hu H, Xu D. Encapsulation and Delivery of Dimethylcurcumin by Using Nanoparticles of a Polyethylene‐Glycol‐Based Dimethylcurcumin Prodrug. ChemistrySelect 2021. [DOI: 10.1002/slct.202100239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Chao Lai
- National & Local Joint Engineering Research Center for High-efficiency Refining and High-quality Utilization of Biomass School of Pharmacy, Changzhou University Changzhou 213164 P. R. China
| | - Hang Hu
- National & Local Joint Engineering Research Center for High-efficiency Refining and High-quality Utilization of Biomass School of Pharmacy, Changzhou University Changzhou 213164 P. R. China
| | - Defeng Xu
- National & Local Joint Engineering Research Center for High-efficiency Refining and High-quality Utilization of Biomass School of Pharmacy, Changzhou University Changzhou 213164 P. R. China
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18
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Lee MT. Designing Highly Conductive Block Copolymer-Based Anion Exchange Membranes by Mesoscale Simulations. J Phys Chem B 2021; 125:2729-2740. [PMID: 33719456 DOI: 10.1021/acs.jpcb.0c10909] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Hydroxide ion conductivity is a key aspect of anion exchange membranes and is mainly determined by the nanoscale membrane morphologies. Fundamental understanding of the structural and transport properties of membranes in terms of polymer architectures is crucial for future development of membrane-based applications. Using mesoscale simulations, this work predicts the mesostructure of the hydrated triblock copolymers; the designed polymers are composed of aromatic (polyphenylene oxide, PPO) or aliphatic (polystyrene-ethylene-butylene-styrene, SEBS) backbones, with cationic side chains being modified by hydrophobic or hydrophilic spacers. For PPO-based polymers, using octyl spacers creates a meshlike water network, yielding ion conductivity equal to 30.6 mS/cm at room temperature. For SEBS-based polymers, the nonmodified form is sufficient to produce ion-conducting pathways. Adding hydrophobic spacers further enhances the nanosegregation, and the membranes provide similar conductivity at a lower ion exchange capacity and water content. Adding hydrophilic spacers, however, has negative impacts on the ion transport. The side chains are in the stretched configurations, which sterically hinder the mobility of water and hydroxide ions. Such a resistance can be overcome by adapting multication side-chain designs, where large water channels are formed, yielding ion conductivity as high as 32.8 mS/cm.
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Affiliation(s)
- Ming-Tsung Lee
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 10608, Taiwan
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19
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Šindelka K, Lísal M. Interplay between surfactant self-assembly and adsorption at hydrophobic surfaces: insights from dissipative particle dynamics. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1857863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Karel Šindelka
- Department of Molecular and Mesoscopic Modelling, The Czech Academy of Sciences, Institute of Chemical Process Fundamentals, Prague, Czech Republic
| | - Martin Lísal
- Department of Molecular and Mesoscopic Modelling, The Czech Academy of Sciences, Institute of Chemical Process Fundamentals, Prague, Czech Republic
- Department of Physics, Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, Ústí nad Labem, Czech Republic
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20
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Bunker A, Róg T. Mechanistic Understanding From Molecular Dynamics Simulation in Pharmaceutical Research 1: Drug Delivery. Front Mol Biosci 2020; 7:604770. [PMID: 33330633 PMCID: PMC7732618 DOI: 10.3389/fmolb.2020.604770] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022] Open
Abstract
In this review, we outline the growing role that molecular dynamics simulation is able to play as a design tool in drug delivery. We cover both the pharmaceutical and computational backgrounds, in a pedagogical fashion, as this review is designed to be equally accessible to pharmaceutical researchers interested in what this new computational tool is capable of and experts in molecular modeling who wish to pursue pharmaceutical applications as a context for their research. The field has become too broad for us to concisely describe all work that has been carried out; many comprehensive reviews on subtopics of this area are cited. We discuss the insight molecular dynamics modeling has provided in dissolution and solubility, however, the majority of the discussion is focused on nanomedicine: the development of nanoscale drug delivery vehicles. Here we focus on three areas where molecular dynamics modeling has had a particularly strong impact: (1) behavior in the bloodstream and protective polymer corona, (2) Drug loading and controlled release, and (3) Nanoparticle interaction with both model and biological membranes. We conclude with some thoughts on the role that molecular dynamics simulation can grow to play in the development of new drug delivery systems.
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Affiliation(s)
- Alex Bunker
- Division of Pharmaceutical Biosciences, Drug Research Program, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Tomasz Róg
- Department of Physics, University of Helsinki, Helsinki, Finland
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21
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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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22
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Zhou J, Ranjith PG. Self-assembly and viscosity changes of binary surfactant solutions: A molecular dynamics study. J Colloid Interface Sci 2020; 585:250-257. [PMID: 33285463 DOI: 10.1016/j.jcis.2020.11.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 11/15/2022]
Abstract
HYPOTHESIS Structure and self-assembly of surfactants in the solution shows a fundamental influence on its viscosity. Through molecular simulations using Martini force field, synergistic effects in aggregation as well as the viscosity changes of a binary ionic surfactant system can be modelled. Simulations: Coarse-grained molecular dynamics simulations are performed to model the SDS/CAPB binary surfactant solution, and both equilibrium and non-equilibrium methods are used to calculate the viscosity of the equilibrated micellar systems. FINDINGS Our simulation results indicate that the new version of the Martini force field can provide more reasonable self-assembly of surfactant, both single and binary system. Synergistic effects in micelle formation for SDS/CAPB have been successfully reproduced, that is, the formation of cylindrical micelles or even wormlike micelles at a lower concentration when compared with the pure system. Meanwhile, both equilibrium and non-equilibrium methods provide quantitatively comparable viscosity for each system. For pure micellar system, the viscosity linearly increases with the total concentration. Nevertheless, our simulation fails to capture the viscosity enhancement of the solution in corresponding with the formation of rodlike or wormlike micelles, and a full parameter optimization of force field is still necessary.
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Affiliation(s)
- Jun Zhou
- Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800, Australia
| | - P G Ranjith
- Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800, Australia.
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23
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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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24
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Klebes J, Finnigan S, Bray DJ, Anderson RL, Swope WC, Johnston MA, Conchuir BO. The Role of Chemical Heterogeneity in Surfactant Adsorption at Solid-Liquid Interfaces. J Chem Theory Comput 2020; 16:7135-7147. [PMID: 33081471 DOI: 10.1021/acs.jctc.0c00759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chemical heterogeneity of solid surfaces disrupts the adsorption of surfactants from the bulk liquid. While its presence can hinder the performance of some formulations, bespoke chemical patterning could potentially facilitate controlled adsorption for nanolithography applications. Although some computational studies have investigated the impact of regularly patterned surfaces on surfactant adsorption, in reality, many interesting surfaces are expected to be stochastically disordered and this is an area unexplored via simulations. In this paper, we describe a new algorithm for the generation of randomly disordered chemically heterogeneous surfaces and use it to explore the adsorption behavior of four model nonionic surfactants. Using novel analysis methods, we interrogate both the global surface coverage (adsorption isotherm) and behavior in localized regions. We observe that trends in adsorption characteristics as surfactant size, head/tail ratio, and surface topology are varied and connect these to underlying physical mechanisms. We believe that our methods and approach will prove useful to researchers seeking to tailor surface patterns to calibrate nonionic surfactant adsorption.
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Affiliation(s)
- Jason Klebes
- IBM Research Europe, The Hartree Centre, Daresbury, Warrington WA4 4AD, United Kingdom.,School of Mathematics, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sophie Finnigan
- IBM Research Europe, The Hartree Centre, Daresbury, Warrington WA4 4AD, United Kingdom.,Department of Chemistry, Molecular Sciences Research Hub, White City Campus, Imperial College London, Wood Lane, London W12 0BZ, United Kingdom
| | - 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
| | - William C Swope
- IBM Almaden Research Center, San Jose, California 95120, United States
| | | | - Breanndan O Conchuir
- IBM Research Europe, The Hartree Centre, Daresbury, Warrington WA4 4AD, United Kingdom
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25
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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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26
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McDonagh JL, Swope WC, Anderson RL, Johnston MA, Bray DJ. What can digitisation do for formulated product innovation and development? POLYM INT 2020. [DOI: 10.1002/pi.6056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | | | | | | | - David J Bray
- The Hartree Centre STFC Daresbury Laboratory Warrington WA4 4AD UK
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27
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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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28
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Lavagnini E, Cook JL, Warren PB, Williamson MJ, Hunter CA. A Surface Site Interaction Point Method for Dissipative Particle Dynamics Parametrization: Application to Alkyl Ethoxylate Surfactant Self-Assembly. J Phys Chem B 2020; 124:5047-5055. [PMID: 32510951 PMCID: PMC7309324 DOI: 10.1021/acs.jpcb.0c01895] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
![]()
Dissipative
particle dynamics (DPD) is a coarse-grained approach
to the simulation of large supramolecular systems, but one limitation
has been that the parameters required to describe the noncovalent
interactions between beads are not readily accessible. A first-principles
computational method has been developed so that bead interaction parameters
can be calculated directly from ab initio gas-phase
molecular electrostatic potential surfaces of the molecular fragments
that represent the beads. A footprinting algorithm converts the molecular
electrostatic potential surfaces into a discrete set of surface site
interaction points (SSIPs), and these SSIPs are used in the SSIMPLE
(surface site interaction model for the properties of liquids at equilibrium)
algorithm to calculate the free energies of transfer of one bead into
a solution of any other bead. The bead transfer free energies are
then converted into the required DPD interaction parameters for all
pairwise combinations of different beads. The reliability of the parameters
was demonstrated using DPD simulations of a range of alkyl ethoxylate
surfactants. The simulations reproduce the experimentally determined
values of the critical micelle concentration and mean aggregation
number well for all 22 surfactants studied.
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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
| | - Mark J Williamson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Christopher A Hunter
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
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29
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Bray DJ, Del Regno A, Anderson RL. UMMAP: a statistical analysis software package for molecular modelling. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1699656] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- David J. Bray
- The Hartree Centre, STFC Daresbury Laboratory, Warrington, UK
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30
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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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31
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Khedr A, Striolo A. Quantification of Ostwald Ripening in Emulsions via Coarse-Grained Simulations. J Chem Theory Comput 2019; 15:5058-5068. [PMID: 31411875 DOI: 10.1021/acs.jctc.9b00296] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ostwald ripening is a diffusional mass transfer process that occurs in polydisperse emulsions, often with the result of threatening the emulsion stability. In this work, we design a simulation protocol that is capable of quantifying the process of Ostwald ripening at the molecular level. To achieve experimentally relevant time scales, the dissipative particle dynamics (DPD) simulation protocol is implemented. The simulation parameters are tuned to represent two benzene droplets dispersed in water. The coalescence between the two droplets is prevented via the introduction of membranes, which allow diffusion of benzene from one droplet to the other. The simulation results are quantified in terms of the changes in the droplet volume as a function of time. The results are in qualitative agreement with experiments. The agreement with the Lifshitz-Slyozov-Wagner theory becomes quantitative when the simulated solubility and diffusion coefficient of benzene-in-water are considered. The effect of two different surfactants was also investigated. In agreement with both experimental observations and theory, the addition of surfactants at moderate concentrations decreased the Ostwald ripening rate because of the reduction in the interfacial tension between benzene and water; as the surfactant film becomes dense, other phenomena are likely to further delay the Ostwald ripening. In fact, the results suggest that the surfactant that yields higher density at the benzene-water interface delayed more effectively Ostwald ripening. The formation of micelles can also affect the ripening rate, in qualitative agreement with experiments, although our simulations are not conclusive on such effects. Our simulations show that the coarse-grained DPD formalism is able to capture the molecular phenomena related to Ostwald ripening and reveal molecular level features that could help to understand experimental observations. The results could be useful for predicting and eventually controlling the long-term stability of emulsions.
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Affiliation(s)
- Abeer Khedr
- Department of Chemical Engineering , University College London , London WC1E 7JE , United Kingdom
| | - Alberto Striolo
- Department of Chemical Engineering , University College London , London WC1E 7JE , United Kingdom
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32
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Mysona JA, McCormick AV, Morse DC. Simulation of diblock copolymer surfactants. I. Micelle free energies. Phys Rev E 2019; 100:012602. [PMID: 31499857 DOI: 10.1103/physreve.100.012602] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Indexed: 06/10/2023]
Abstract
Semigrand hybrid Monte Carlo simulations are used to measure equilibrium properties of micelles formed in a simple bead-spring model of asymmetric A-B diblock copolymer surfactant molecules in an A homopolymer solvent, over a range of values of surfactant solubility. Simulations are used to accurately measure the free energy of formation of micellar clusters as a function of aggregation number over a wide range of values, and to characterize the crossover from spherical to rodlike micelle shape with increasing aggregation number. Dynamical properties of the same model are considered in an accompanying paper [Phys. Rev. E 100, 012603 (2019)10.1103/PhysRevE.100.012603].
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Affiliation(s)
- Joshua A Mysona
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - Alon V McCormick
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - David C Morse
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
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33
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Eslami H, Khani M, Müller-Plathe F. Gaussian Charge Distributions for Incorporation of Electrostatic Interactions in Dissipative Particle Dynamics: Application to Self-Assembly of Surfactants. J Chem Theory Comput 2019; 15:4197-4207. [DOI: 10.1021/acs.jctc.9b00174] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Hossein Eslami
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Marzieh Khani
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
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34
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Wessels MG, Jayaraman A. Molecular dynamics simulation study of linear, bottlebrush, and star-like amphiphilic block polymer assembly in solution. SOFT MATTER 2019; 15:3987-3998. [PMID: 31025695 DOI: 10.1039/c9sm00375d] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this study we investigate the effect of varying branched polymer architectures on the assembly of amphiphilic block polymers in solution using coarse-grained molecular dynamics simulations. We quantify assembly structure (e.g., aggregation number, assembly morphology, and micelle core size) and thermodynamics (e.g., unimer to micelle transition conditions) as a function of increasing solvophobicity of the solvophobic block in the copolymer for three broad categories of polymer architectures: linear, 'bottlebrush' (with many short side chains on a long backbone), and 'star-like' (with few long side chains on a short backbone). Keeping the total number of coarse-grained beads in each polymer (or polymer molecular weight) constant, as we go from either linear or 'star-like' to 'bottlebrush' polymer architectures, the micelle aggregation number and micelle core size decrease, and the solvophobicity required for assembly (i.e., transition solvophobicity) increases. This trend is linked to the topological/steric hinderance for making solvophobic bead contacts between neighboring polymers for the 'bottlebrush' polymer architecture compared to the linear or 'star-like' architectures. We are able to identify some universal trends in assembly by plotting the assembly structure and thermodynamics data as a function of branching parameter defined as the ratio of the branched chain to the linear chain radius of gyration in the unimer state, and the relative lengths of the backbone versus side chain. The results in this paper guide how one could manipulate the amphiphilic block polymer assembly structure and thermodynamics by choosing appropriate polymer architecture, block sequence, and composition.
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Affiliation(s)
- Michiel G Wessels
- Colburn Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
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35
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Kahana A, Lancet D. Protobiotic Systems Chemistry Analyzed by Molecular Dynamics. Life (Basel) 2019; 9:E38. [PMID: 31083329 PMCID: PMC6617412 DOI: 10.3390/life9020038] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 12/16/2022] Open
Abstract
Systems chemistry has been a key component of origin of life research, invoking models of life's inception based on evolving molecular networks. One such model is the graded autocatalysis replication domain (GARD) formalism embodied in a lipid world scenario, which offers rigorous computer simulation based on defined chemical kinetics equations. GARD suggests that the first pre-RNA life-like entities could have been homeostatically-growing assemblies of amphiphiles, undergoing compositional replication and mutations, as well as rudimentary selection and evolution. Recent progress in molecular dynamics has provided an experimental tool to study complex biological phenomena such as protein folding, ligand-receptor interactions, and micellar formation, growth, and fission. The detailed molecular definition of GARD and its inter-molecular catalytic interactions make it highly compatible with molecular dynamics analyses. We present a roadmap for simulating GARD's kinetic and thermodynamic behavior using various molecular dynamics methodologies. We review different approaches for testing the validity of the GARD model by following micellar accretion and fission events and examining compositional changes over time. Near-future computational advances could provide empirical delineation for further system complexification, from simple compositional non-covalent assemblies towards more life-like protocellular entities with covalent chemistry that underlies metabolism and genetic encoding.
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Affiliation(s)
- Amit Kahana
- Dept. Molecular Genetics, The Weizmann Institute of Science, Rehovot 7610010, Israel.
| | - Doron Lancet
- Dept. Molecular Genetics, The Weizmann Institute of Science, Rehovot 7610010, Israel.
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36
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Minkara MS, Hembree RH, Jamadagni SN, Ghobadi AF, Eike DM, Siepmann JI. A new equation of state for homo-polymers in dissipative particle dynamics. J Chem Phys 2019; 150:124104. [PMID: 30927875 DOI: 10.1063/1.5058280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A chain-revised Groot-Warren equation of state (crGW-EOS) was developed and tested to describe systems of homo-oligomeric chains in the framework of dissipative particle dynamics (DPD). First, thermodynamic perturbation theory is applied to introduce correction terms that account for the reduction in pressure with an increasing number of bonds at constant bead number density. Then, this EOS is modified by introducing a set of switching functions that yields an accurate second virial coefficient in the low-density limit. The crGW-EOS offers several improvements over the revised Groot-Warren equation of state and Groot-Warren equation of state for chain molecules. We tested the crGW-EOS by using it to predict the pressure of oligomeric systems and the B2 virial coefficient of chain DPD particles for a range of bond lengths. Additionally, a method is developed for determining the strength of cross-interaction parameters between chains of different compositions and sizes and for thermal and athermal mixtures. We explored how different levels of coarse-graining affect the upper-critical solution temperature.
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Affiliation(s)
- Mona S Minkara
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA
| | - Robert H Hembree
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA
| | - Sumanth N Jamadagni
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company, 8611 Beckett Road, West Chester, Ohio 45069, USA
| | - Ahmad F Ghobadi
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company, 8611 Beckett Road, West Chester, Ohio 45069, USA
| | - David M Eike
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company, 8611 Beckett Road, West Chester, Ohio 45069, USA
| | - J Ilja Siepmann
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA
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37
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Khedr A, Striolo A. DPD Parameters Estimation for Simultaneously Simulating Water–Oil Interfaces and Aqueous Nonionic Surfactants. J Chem Theory Comput 2018; 14:6460-6471. [DOI: 10.1021/acs.jctc.8b00476] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Abeer Khedr
- Chemical Engineering Department, University College London, London, United Kingdom
| | - Alberto Striolo
- Chemical Engineering Department, University College London, London, United Kingdom
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38
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Custer GS, Xu H, Matysiak S, Das P. How Hydrophobic Hydration Destabilizes Surfactant Micelles at Low Temperature: A Coarse-Grained Simulation Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:12590-12599. [PMID: 30247911 DOI: 10.1021/acs.langmuir.8b01994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Micelles are self-assembled aggregates of amphiphilic surfactant molecules that are important in a variety of applications, including drug delivery, detergency, and catalysis. It is known that the micellization process is driven by the same physiochemical forces that drive protein folding, aggregation, and biological membrane self-assembly. Nevertheless, the molecular details of how micelle stability changes in water at low temperature are not fully clear. We develop and use a coarse-grained model to investigate how the interplay between nonionic surfactants and the surrounding water at the nanoscale affects the stability of micelles at high and low temperatures. Simulations of preformed C12E5 micelles in explicit water at a range of temperatures reveal the existence of two distinct surfactant conformations within the micelle, a bent structure and an extended structure, the latter being more prevalent at low temperature. Favorable interactions of the surfactant with more ordered solvation water stabilizes the extended configuration, allowing nanoscale wetting of the dry, hydrophobic core of the micelle, leading to the micelle breaking. Taken together, our coarse-grained simulations unravel how energetic and structural changes of the surfactant and the surrounding water destabilize micelles at low temperature, which is a direct consequence of the weakened hydrophobicity. Our approach thus provides an effective mean for extracting the molecular-level changes during hydrophobicity-driven destabilization of molecular self-assembly, which is important in a wide range of fields, including biology, polymer science, and nanotechnology.
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Affiliation(s)
| | | | | | - Payel Das
- IBM Thomas J. Watson Research Center , Yorktown Heights, New York 10598 , United States
- Department of Applied Physics and Applied Mathematics , Columbia University , New York 10027 , United States
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39
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Seaton MA. DL_MESO_DPD: development and use of mesoscale modelling software. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1524143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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40
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Abstract
Surfaces and interfaces are ubiquitous in nature and are involved in many biological processes. Due to this, natural organisms have evolved a number of methods to control interfacial and surface properties. Many of these methods involve the use of specialised protein biosurfactants, which due to the competing demands of high surface activity, biocompatibility, and low solution aggregation may take structures that differ from the traditional head–tail structure of small molecule surfactants. As well as their biological functions, these proteins have also attracted interest for industrial applications, in areas including food technology, surface modification, and drug delivery. To understand the biological functions and technological applications of protein biosurfactants, it is necessary to have a molecular level description of their behaviour, in particular at surfaces and interfaces, for which molecular simulation is well suited to investigate. In this review, we will give an overview of simulation studies of a number of examples of protein biosurfactants (hydrophobins, surfactin, and ranaspumin). We will also outline some of the key challenges and future directions for molecular simulation in the investigation of protein biosurfactants and how this can help guide future developments.
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41
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Danov KD, Kralchevsky PA, Stoyanov SD, Cook JL, Stott IP, Pelan EG. Growth of wormlike micelles in nonionic surfactant solutions: Quantitative theory vs. experiment. Adv Colloid Interface Sci 2018; 256:1-22. [PMID: 29804690 DOI: 10.1016/j.cis.2018.05.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 11/25/2022]
Abstract
Despite the considerable advances of molecular-thermodynamic theory of micelle growth, agreement between theory and experiment has been achieved only in isolated cases. A general theory that can provide self-consistent quantitative description of the growth of wormlike micelles in mixed surfactant solutions, including the experimentally observed high peaks in viscosity and aggregation number, is still missing. As a step toward the creation of such theory, here we consider the simplest system - nonionic wormlike surfactant micelles from polyoxyethylene alkyl ethers, CiEj. Our goal is to construct a molecular-thermodynamic model that is in agreement with the available experimental data. For this goal, we systematized data for the micelle mean mass aggregation number, from which the micelle growth parameter was determined at various temperatures. None of the available models can give a quantitative description of these data. We constructed a new model, which is based on theoretical expressions for the interfacial-tension, headgroup-steric and chain-conformation components of micelle free energy, along with appropriate expressions for the parameters of the model, including their temperature and curvature dependencies. Special attention was paid to the surfactant chain-conformation free energy, for which a new more general formula was derived. As a result, relatively simple theoretical expressions are obtained. All parameters that enter these expressions are known, which facilitates the theoretical modeling of micelle growth for various nonionic surfactants in excellent agreement with the experiment. The constructed model can serve as a basis that can be further upgraded to obtain quantitative description of micelle growth in more complicated systems, including binary and ternary mixtures of nonionic, ionic and zwitterionic surfactants, which determines the viscosity and stability of various formulations in personal-care and house-hold detergency.
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42
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Hu Y, Charbonneau P. Clustering and assembly dynamics of a one-dimensional microphase former. SOFT MATTER 2018; 14:4101-4109. [PMID: 29578236 DOI: 10.1039/c8sm00315g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Both ordered and disordered microphases ubiquitously form in suspensions of particles that interact through competing short-range attraction and long-range repulsion (SALR). While ordered microphases are more appealing materials targets, understanding the rich structural and dynamical properties of their disordered counterparts is essential to controlling their mesoscale assembly. Here, we study the disordered regime of a one-dimensional (1D) SALR model, whose simplicity enables detailed analysis by transfer matrices and Monte Carlo simulations. We first characterize the signature of the clustering process on macroscopic observables, and then assess the equilibration dynamics of various simulation algorithms. We notably find that cluster moves markedly accelerate the mixing time, but that event chains are of limited help in the clustering regime. These insights will inspire further study of three-dimensional microphase formers.
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Affiliation(s)
- Yi Hu
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
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43
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Anderson RL, Bray DJ, Del Regno A, Seaton MA, Ferrante AS, Warren PB. Micelle Formation in Alkyl Sulfate Surfactants Using Dissipative Particle Dynamics. J Chem Theory Comput 2018; 14:2633-2643. [PMID: 29570296 DOI: 10.1021/acs.jctc.8b00075] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We use dissipative particle dynamics (DPD) to study micelle formation in alkyl sulfate surfactants, with alkyl chain lengths ranging from 6 to 12 carbon atoms. We extend our recent DPD force field [ J. Chem. Phys. 2017 , 147 , 094503 ] to include a charged sulfate chemical group and aqueous sodium ions. With this model, we achieve good agreement with the experimentally reported critical micelle concentrations (CMCs) and can match the trend in mean aggregation numbers versus alkyl chain length. We determine the CMC by fitting a charged pseudophase model to the dependence of the free surfactant on the total surfactant concentration above the CMC and compare it with a direct operational definition of the CMC as the point at which half of the surfactant is classed as micellar and half as monomers and submicellar aggregates. We find that the latter provides the best agreement with experimental results. Finally, with the same model, we are able to observe the sphere-to-rod morphological transition for sodium dodecyl sulfate (SDS) micelles and determine that it corresponds to SDS concentrations in the region of 300-500 mM.
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Affiliation(s)
- Richard L Anderson
- STFC Hartree Centre, Scitech Daresbury , Warrington WA4 4AD , United Kingdom
| | - David J Bray
- STFC Hartree Centre, Scitech Daresbury , Warrington WA4 4AD , United Kingdom
| | - Annalaura Del Regno
- STFC Hartree Centre, Scitech Daresbury , Warrington WA4 4AD , United Kingdom
| | - Michael A Seaton
- STFC Hartree Centre, Scitech Daresbury , Warrington WA4 4AD , United Kingdom
| | - Andrea S Ferrante
- Ferrante Scientific Ltd. , 5 Croft Lane , Bromborough CH62 2BX , United Kingdom
| | - Patrick B Warren
- Unilever R&D Port Sunlight , Quarry Road East , Bebington CH63 3JW , United Kingdom
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Wang H, Tang X, Eike DM, Larson RG, Koenig PH. Scission Free Energies for Wormlike Surfactant Micelles: Development of a Simulation Protocol, Application, and Validation for Personal Care Formulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:1564-1573. [PMID: 29244513 DOI: 10.1021/acs.langmuir.7b03552] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a scheme to calculate wormlike micelle scission free energies from a potential of mean force (PMF) derived from a weighted histogram analysis method (WHAM) applied to coarse grained dissipative particle dynamics (DPD) simulations. In contrast to previous related work, we use a specially chosen external potential based on a reaction coordinate that reversibly drives surfactants out of the nascent scission location. For the application to a model body wash formulation, we predict how addition of NaCl and small molecules such as perfume raw materials (PRMs) affect scission energies. The results show qualitative agreement and correct trends compared to recently determined scission energies for the same system; however, a more rigorous parametrization of the underlying DPD potential is required for quantitative agreement.
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Affiliation(s)
- Huan Wang
- University of Cincinnati Simulation Center , 2728 Vine Street, Cincinnati, Ohio 45220, United States
| | - Xueming Tang
- Department of Chemical Engineering, 2800 Plymouth Road, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - David M Eike
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company , 8611 Beckett Road, West Chester, Ohio 45069, United States
| | - Ronald G Larson
- Department of Chemical Engineering, 2800 Plymouth Road, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Peter H Koenig
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company , 8611 Beckett Road, West Chester, Ohio 45069, United States
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Zhang X, Patel LA, Beckwith O, Schneider R, Weeden CJ, Kindt JT. Extracting Aggregation Free Energies of Mixed Clusters from Simulations of Small Systems: Application to Ionic Surfactant Micelles. J Chem Theory Comput 2017; 13:5195-5206. [PMID: 28942641 DOI: 10.1021/acs.jctc.7b00671] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Micelle cluster distributions from molecular dynamics simulations of a solvent-free coarse-grained model of sodium octyl sulfate (SOS) were analyzed using an improved method to extract equilibrium association constants from small-system simulations containing one or two micelle clusters at equilibrium with free surfactants and counterions. The statistical-thermodynamic and mathematical foundations of this partition-enabled analysis of cluster histograms (PEACH) approach are presented. A dramatic reduction in computational time for analysis was achieved through a strategy similar to the selector variable method to circumvent the need for exhaustive enumeration of the possible partitions of surfactants and counterions into clusters. Using statistics from a set of small-system (up to 60 SOS molecules) simulations as input, equilibrium association constants for micelle clusters were obtained as a function of both number of surfactants and number of associated counterions through a global fitting procedure. The resulting free energies were able to accurately predict micelle size and charge distributions in a large (560 molecule) system. The evolution of micelle size and charge with SOS concentration as predicted by the PEACH-derived free energies and by a phenomenological four-parameter model fit, along with the sensitivity of these predictions to variations in cluster definitions, are analyzed and discussed.
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Affiliation(s)
- X Zhang
- Department of Chemistry and ‡Department of Mathematics and Computer Science, Emory University , Atlanta, Georgia 30322, United States
| | - L A Patel
- Department of Chemistry and ‡Department of Mathematics and Computer Science, Emory University , Atlanta, Georgia 30322, United States
| | - O Beckwith
- Department of Chemistry and ‡Department of Mathematics and Computer Science, Emory University , Atlanta, Georgia 30322, United States
| | - R Schneider
- Department of Chemistry and ‡Department of Mathematics and Computer Science, Emory University , Atlanta, Georgia 30322, United States
| | - C J Weeden
- Department of Chemistry and ‡Department of Mathematics and Computer Science, Emory University , Atlanta, Georgia 30322, United States
| | - J T Kindt
- Department of Chemistry and ‡Department of Mathematics and Computer Science, Emory University , Atlanta, Georgia 30322, United States
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46
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Anderson RL, Bray DJ, Ferrante AS, Noro MG, Stott IP, Warren PB. Dissipative particle dynamics: Systematic parametrization using water-octanol partition coefficients. J Chem Phys 2017; 147:094503. [DOI: 10.1063/1.4992111] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - David J. Bray
- STFC Hartree Centre, Scitech Daresbury, Warrington WA4 4AD, United Kingdom
| | - Andrea S. Ferrante
- Novidec Ltd., 3 Brook Hey, Parkgate, Neston CH64 6TH, United Kingdom
- Ferrante Scientific Ltd., 5 Croft Lane, Bromborough CH62 2BX, United Kingdom
| | - Massimo G. Noro
- Unilever R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, United Kingdom
| | - Ian P. Stott
- Unilever R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, United Kingdom
| | - Patrick B. Warren
- Unilever R&D Port Sunlight, Quarry Road East, Bebington CH63 3JW, United Kingdom
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Affiliation(s)
- Pep Español
- Dept. Física Fundamental, Universidad Nacional de Educación a Distancia, Aptdo. 60141, E-28080 Madrid, Spain
| | - Patrick B. Warren
- Unilever R&D Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, United Kingdom
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48
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Patel LA, Kindt JT. Cluster Free Energies from Simple Simulations of Small Numbers of Aggregants: Nucleation of Liquid MTBE from Vapor and Aqueous Phases. J Chem Theory Comput 2017; 13:1023-1033. [DOI: 10.1021/acs.jctc.6b01237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lara A. Patel
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - James T. Kindt
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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