1
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Silva P, Silva GMC, Morgado P, Fauré MC, Goldmann M, Filipe EJM. Origin of the central pit in hemimicelles of semifluorinated alkanes: How molecular dipoles and substrate deformation can determine supra-molecular morphology. J Colloid Interface Sci 2024; 655:576-583. [PMID: 37956545 DOI: 10.1016/j.jcis.2023.11.007] [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: 04/11/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023]
Abstract
HYPOTHESIS Semifluorinated alkanes amphiphiles spontaneously form highly monodispersed hemimicelles at the surface of water. The origin of the formation and complex structure of these surprising supramolecular aggregates were only recently clarified using molecular dynamics simulations (MD). The existence of a pit at the center of these aggregates made up of almost 3000 molecules was indeed reproduced by the MD simulations, but not understood. METHOD A careful strategy of atomistic MD simulations comparing non-electrostatic force fields with force fields that include electrostatic forces, thus bearing an implicit or explicit dipole, allowed demonstrating the roles of dipolar interactions and interactions with the liquid subphase on the morphology of the aggregates. FINDINGS The simulation results clearly show that within the hemimicelles the strong molecular dipoles located at the CH2-CF2 junctions tend to align, leading to a collective shift of the PFAA molecules relatively to each other. This shift is responsible for the curvature of the hemimicelles and originates the central pit, provided the possibility of deforming the surface of the water sub-phase. Comparisons with non-electrostatic force field results further contribute to understand the origin of the self-assembling process. The results directly connect for the first time a molecular property with a mesoscopic structural feature. Given the molecular simplicity of these "primitive" amphiphiles compared to the common hydrophilic/hydrophobic surfactants, the results contribute to understand self-assembly in general.
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Affiliation(s)
- Pedro Silva
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; Sorbonne Université, Institut des NanoSciences de Paris, CNRS-UMR 7588, 4 place Jussieu, 75005 Paris, France
| | - Gonçalo M C Silva
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Pedro Morgado
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Marie-Claude Fauré
- Sorbonne Université, Institut des NanoSciences de Paris, CNRS-UMR 7588, 4 place Jussieu, 75005 Paris, France; Université Paris Cité, UFR des Sciences Fondamentales et Biomédicales, 45 Rue de Saints-Pères, 75006 Paris, France
| | - Michel Goldmann
- Sorbonne Université, Institut des NanoSciences de Paris, CNRS-UMR 7588, 4 place Jussieu, 75005 Paris, France; Université Paris Cité, UFR des Sciences Fondamentales et Biomédicales, 45 Rue de Saints-Pères, 75006 Paris, France; Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP48, 91192 Gif-Sur-Yvette, France
| | - Eduardo J M Filipe
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
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2
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Smith ER, Theodorakis PE. Multiscale simulation of fluids: coupling molecular and continuum. Phys Chem Chem Phys 2024; 26:724-744. [PMID: 38113114 DOI: 10.1039/d3cp03579d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Computer simulation is an important tool for scientific progress, especially when lab experiments are either extremely costly and difficult or lack the required resolution. However, all of the simulation methods come with limitations. In molecular dynamics (MD) simulation, the length and time scales that can be captured are limited, while computational fluid dynamics (CFD) methods are built on a range of assumptions, from the continuum hypothesis itself, to a variety of closure assumptions. To address these issues, the coupling of different methodologies provides a way to retain the best of both methods. Here, we provide a perspective on multiscale simulation based on the coupling of MD and CFD with each a distinct part of the same simulation domain. This style of coupling allows molecular detail to be present only where it is needed, so CFD can model larger scales than possible with MD alone. We present a unified perspective of the literature, showing the links between the two main types of coupling, state and flux, and discuss the varying assumptions in their use. A unique challenge in such coupled simulation is obtaining averages and constraining local parts of a molecular simulation. We highlight that incorrect localisation has resulted in an error in the literature. We then finish with some applications, focused on the simulation of fluids. Thus, we hope to motivate further research in this exciting area with applications across the spectrum of scientific disciplines.
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Affiliation(s)
- Edward R Smith
- Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge, Middlesex UB8 3PH, UK.
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3
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Arbabi S, Deuar P, Denys M, Bennacer R, Che Z, Theodorakis PE. Molecular dynamics simulation of the coalescence of surfactant-laden droplets. SOFT MATTER 2023; 19:8070-8080. [PMID: 37801284 DOI: 10.1039/d3sm01046e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
We investigate the coalescence of surfactant-laden water droplets by using several different surfactant types and a wide range of concentrations by means of a coarse-grained model obtained by the statistical associating fluid theory. Our results demonstrate in detail a universal mass transport mechanism of surfactant across many concentrations and several surfactant types during the process. Coalescence initiation is seen to occur via a single pinch due to aggregation of surface surfactant, and its remnants tend to become engulfed in part inside the forming bridge. Across the board we confirm the existence of an initial thermal regime with constant bridge width followed by a later inertial regime with bridge width scaling roughly as the square root of time, but see no evidence of an intermediate viscous regime. Coalescence becomes slower as surfactant concentration grows, and we see evidence of the appearance of a further slowdown of a different nature for several times the critical concentration. We anticipate that our results provide further insights in the mechanisms of coalescence of surfactant-laden droplets.
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Affiliation(s)
- Soheil Arbabi
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Piotr Deuar
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Mateusz Denys
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Rachid Bennacer
- Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS - Laboratoire de Mécanique Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Zhizhao Che
- State Key Laboratory of Engines, Tianjin University, 300350 Tianjin, China
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4
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Silva GM, Beira MJ, Morgado P, Branco LC, Sebastião PJ, Canongia Lopes JN, Filipe EJ. Ionic liquids with hydrogenated and perfluorinated chains: Structural study of the [P6,6,6,14][FnCOO] n = 7, 9, 11. Checking the existence of polar – hydrogenated – perfluorinated triphilic continuity. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Cabaço MI, Besnard M, Cruz C, Morgado P, Silva GC, Filipe EJM, Coutinho JA, Danten Y. Breaking the Structure of Liquid Hydrogenated Alcohols Using Perfluorinated tert-Butanol: A Multitechnique Approach (Infrared, Raman, and X-ray Scattering) Analyzed by DFT and Molecular Dynamics Calculations. J Phys Chem B 2022; 126:1992-2004. [PMID: 35230118 PMCID: PMC9776561 DOI: 10.1021/acs.jpcb.1c10776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The state of aggregation at room temperature of tert-butanol (TBH) and perfluoro tert-butanol (TBF) liquid mixtures is assessed by vibrational spectroscopy (Raman and infrared) and X-ray diffraction and analyzed using density functional theory (DFT) and molecular dynamics (MD) simulations. It is shown that larger clusters (mostly tetramers) of TBH are destroyed upon dilution with TBF. Small oligomers, monomers, and mainly heterodimers are present at the equimolar concentration. At variance with slightly interacting solvents, the signature of hetero-oligomers is shown by the appearance of a new broad band detected in the infrared region. The same spectral observation is detected for mixtures of other hydrogenated alcohols (methanol and 1-butanol). The new infrared feature is unaffected by dilution in a polar solvent (CDCl3) in a high-concentration domain, allowing us to assign it to the signature of small hetero-oligomers. MD simulations are used to assess the nature of the species present in the mixture (monomers and small hetero-oligomers) and to follow the evolution of their population upon the dilution. Combining MD simulations with DFT calculations, the infrared spectral profile is successfully analyzed in equimolecular mixtures. This study shows that TBF is a structure breaker of hydrogen-bonded alcohol networks and that the TBF (donor)-TBH (acceptor) heterodimer is the dominant species in an extended range of concentration, centered in the vicinity of the equimolar fraction.
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Affiliation(s)
- M. Isabel Cabaço
- CeFEMA,
Centro de Física e Engenharia de Materiais Avançados,
Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal,Laboratory
of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL),
Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal,
| | - Marcel Besnard
- CeFEMA,
Centro de Física e Engenharia de Materiais Avançados,
Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal,GSM
Institut des Sciences Moléculaires, CNRS (UMR 5255), Université Bordeaux I, 351, Cours de la Libération, 33405 Talence Cedex, France
| | - Carlos Cruz
- CeFEMA,
Centro de Física e Engenharia de Materiais Avançados,
Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Pedro Morgado
- Centro
de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
| | - Gonçalo
M. C. Silva
- Centro
de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
| | - Eduardo J. M. Filipe
- Centro
de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
| | - João A.
P. Coutinho
- CICECO,
Departamento de Química, Universidade
de Aveiro, 3810-193 Aveiro, Portugal
| | - Yann Danten
- GSM
Institut des Sciences Moléculaires, CNRS (UMR 5255), Université Bordeaux I, 351, Cours de la Libération, 33405 Talence Cedex, France
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6
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Fayaz-Torshizi M, Xu W, Vella JR, Marshall BD, Ravikovitch PI, Müller EA. Use of Boundary-Driven Nonequilibrium Molecular Dynamics for Determining Transport Diffusivities of Multicomponent Mixtures in Nanoporous Materials. J Phys Chem B 2022; 126:1085-1100. [PMID: 35104134 PMCID: PMC9007456 DOI: 10.1021/acs.jpcb.1c09159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The boundary-driven molecular modeling
strategy to evaluate mass
transport coefficients of fluids in nanoconfined media is revisited
and expanded to multicomponent mixtures. The method requires setting
up a simulation with bulk fluid reservoirs upstream and downstream
of a porous media. A fluid flow is induced by applying an external
force at the periodic boundary between the upstream and downstream
reservoirs. The relationship between the resulting flow and the density
gradient of the adsorbed fluid at the entrance/exit of the porous
media provides for a direct path for the calculation of the transport
diffusivities. It is shown how the transport diffusivities found this
way relate to the collective, Onsager, and self-diffusion coefficients,
typically used in other contexts to describe fluid transport in porous
media. Examples are provided by calculating the diffusion coefficients
of a Lennard-Jones (LJ) fluid and mixtures of differently sized LJ
particles in slit pores, a realistic model of methane in carbon-based
slit pores, and binary mixtures of methane with hypothetical counterparts
having different attractions to the solid. The method is seen to be
robust and particularly suited for the study of study of transport
of dense fluids and liquids in nanoconfined media.
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Affiliation(s)
- Maziar Fayaz-Torshizi
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Weilun Xu
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Joseph R Vella
- ExxonMobil Research and Engineering Company, Irving, Texas 75039-2298, United States
| | - Bennett D Marshall
- ExxonMobil Research and Engineering Company, Annandale, New Jersey 08801, United States
| | - Peter I Ravikovitch
- ExxonMobil Research and Engineering Company, Annandale, New Jersey 08801, United States
| | - Erich A Müller
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
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7
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Yadav HOS, Harada S, Kuo AT, Urata S, Shinoda W. Hemimicelle formation of semi-fluorocarbon chains at air–water interface: coarse-grained molecular dynamics study with an extension of the SPICA force field. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1910355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Hari O. S. Yadav
- Department of Materials Chemistry, Nagoya University, Nagoya, Japan
| | - Shogo Harada
- Department of Materials Chemistry, Nagoya University, Nagoya, Japan
| | - An-Tsung Kuo
- Innovative Technology Laboratories, AGC Inc., Yokohama, Japan
| | - Shingo Urata
- Innovative Technology Laboratories, AGC Inc., Yokohama, Japan
| | - Wataru Shinoda
- Department of Materials Chemistry, Nagoya University, Nagoya, Japan
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8
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Fayaz‐Torshizi M, Müller EA. Coarse‐Grained Molecular Simulation of Polymers Supported by the Use of the SAFT‐γ$\gamma$ Mie Equation of State. MACROMOL THEOR SIMUL 2021. [DOI: 10.1002/mats.202100031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Erich A. Müller
- Department of Chemical Engineering Imperial College London London SW7 2AZ UK
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9
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Morgado P, Barras J, Galindo A, Jackson G, Filipe EJM. Solubility of water in mixtures of ( n-alkanes + n-perfluoroalkanes) and in n-perfluoroalkylalkanes: experiments and modelling with the SAFT- γ Mie group-contribution approach. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1910743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Pedro Morgado
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - João Barras
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
- Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Amparo Galindo
- Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, South Kensington Campus, London, UK
| | - George Jackson
- Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Eduardo J. M. Filipe
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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10
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Clark JA, Santiso EE. SAFT-γ-Mie Cross-Interaction Parameters from Density Functional Theory-Predicted Multipoles of Molecular Fragments for Carbon Dioxide, Benzene, Alkanes, and Water. J Phys Chem B 2021; 125:3867-3882. [PMID: 33826844 DOI: 10.1021/acs.jpcb.1c00851] [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
Determining unlike-pair interaction parameters, whether for group contribution equation of state or molecular simulations, is a challenge for the prediction of thermodynamic properties. As the number of components and their respective complexity increase, it becomes impractical to fit all the unlike interactions. Lorentz-Berthelot combining rules work well for systems, where the main interactions are dispersion forces, but they do not account for electrostatics. In this work, we derive predictive combining rules within the SAFT-γ-Mie framework. In the resulting model, the unlike-pair interactions account for the effect of ionization energies, partial charges, dipole moments, and quadrupole moments. We then estimate these properties for molecular fragments using density functional theory calculations and demonstrate their use to obtain realistic cross-interaction energies without the need for experimental data. An open-source python package, Multipole Approach to Predictively Scale Cross-Interactions, is included to facilitate use of the methods presented in this work. A good qualitative agreement was obtained for all phase equilibria calculations of binary mixtures containing carbon dioxide with propane, hexane, benzene, and water, as well as mixtures of hexane and benzene. Finally, we discuss future improvements to our methodology, including the use of physical insights when fitting self-interaction parameters.
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Affiliation(s)
- Jennifer A Clark
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, 27695, United States
| | - Erik E Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, 27695, United States
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11
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Song J, Wan M, Yang Y, Gao L, Fang W. Development of accurate coarse-grained force fields for weakly polar groups by an indirect parameterization strategy. Phys Chem Chem Phys 2021; 23:6763-6774. [PMID: 33720253 DOI: 10.1039/d1cp00032b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Coarse-grained (CG) molecular dynamics simulations are widely used to predict morphological structures and interpret mechanisms of mesoscopic behavior between the scope of traditional experiments and all-atom simulations. However, most current CG force fields (FFs) are not precise enough, especially for polar molecules or functional groups. A main obstacle in developing accurate CG FFs for polar molecules is the freezing problem met at room temperature. In this work, we introduce an indirect parametrization strategy for weakly polar groups by considering their short-chain homologs to avoid freezing. Here, a polar group containing three to four heavy atoms is mapped into one CG bead that is connected to one alkyl bead composed of three or four carbons. The CG beads interact via 4-parameter nonbonded Morse potentials and harmonic bonded potentials. An efficient meta-multilinear interpolation parameterization algorithm, as recently developed by us, is used to rigorously optimize the force parameters. Satisfactory accuracy is witnessed in terms of the density, heat of vaporization, surface tension, and solvation free energy of the homologs of twelve polar molecules, all deviating from the experiment by less than 5%. The transferability of the current FF is indicated by the predicted density, heat of vaporization, and end-to-end distance distributions of fatty acid methyl esters composed of multiple functional groups parameterized in this work.
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Affiliation(s)
- Junjie Song
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China.
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12
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Walker CC, Genzer J, Santiso EE. Effect of Poly(vinyl butyral) Comonomer Sequence on Adhesion to Amorphous Silica: A Coarse-Grained Molecular Dynamics Study. ACS APPLIED MATERIALS & INTERFACES 2020; 12:47879-47890. [PMID: 32921047 DOI: 10.1021/acsami.0c10747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Modulating a comonomer sequence, in addition to the overall chemical composition, is the key to unlocking the true potential of many existing commercial copolymers. We employ coarse-grained molecular dynamics (MD) simulations to study the behavior of random-blocky poly(vinyl butyral-co-vinyl alcohol) (PVB) melts in contact with an amorphous silica surface, representing the interface found in laminated safety glass. Our two-pronged coarse-graining approach utilizes both macroscopic thermophysical data and all-atom MD simulation data. Polymer-polymer nonbonded interactions are described by the fused-sphere SAFT-γ Mie equation of state, while bonded interactions are derived using Boltzmann inversion to match the bond and angle distributions from all-atom PVB chains. Spatially dependent polymer-surface interactions are mapped from a hydroxylated all-atom amorphous silica slab model and all-atom monomers to an external potential acting on the coarse-grained sites. We discovered an unexpected complex relationship between the blockiness parameter and the adhesion energy. The adhesion strength between PVB copolymers with intermediate VA content and silica was found to be maximal for random-blocky copolymers with a moderately high degree of blockiness rather than for diblock copolymers. We attribute this to two main factors: (1) changes in morphology, which dramatically alter the number of VA beads interacting with the surface and (2) a non-negligible contribution of vinyl butyral (VB) monomers to adhesion energy because of their preference to adsorb to zones with low hydroxyl density on the silica surface.
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Affiliation(s)
- Christopher C Walker
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jan Genzer
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Erik E Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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13
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Liquid–liquid interfaces: Water–perfluoroalkanes and water–perfluoroalkylalkanes, experimental interfacial tensions and molecular simulation. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113385] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Morgado P, Barras J, Filipe EJM. From nano-seggregation to mesophases: probing the liquid structure of perfluoroalkylalkanes with 129Xe NMR spectroscopy. Phys Chem Chem Phys 2020; 22:14736-14747. [PMID: 32578615 DOI: 10.1039/d0cp02123g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work we demonstrate that pure perfluoroalkylalkane diblock molecules are not isotropic liquids and self organize forming domains at the nanometric scale. 129Xe NMR spectra were obtained as a function of temperature for seven liquid perfluoroalkylalkanes, covering a range of relative lengths of the hydrogenated and fluorinated segments. The results support the presence of domains richer in the hydrogenated groups, in which xenon is preferentially dissolved. The average local concentration within the xenon coordination sphere is estimated to be 0.05 mole fraction higher in hydrogenated groups than the stoichiometric proportion. Atomistic molecular dynamics simulations support this analysis and allow a detailed analysis of the liquid structure. Furthermore, 129Xe NMR spectra in perfluorohexylhexane (F6H6) and perfluorohexyloctane (F6H8) obtained as a function of temperature, clearly detect the existence of two distinct environments in the fluid, one richer in hydrogenated groups and another richer in fluorinated groups, consistent with the formation of mesophases. It is important to stress that nano-segregation is this case observed in liquids interacting exclusively through dispersion forces, unlike most common examples of segregation which are determined by hydrogen bonding and polarity. Given the simple molecular structure and interactions of the studied PFAA, we believe that the present results can have a general impact in understanding the early mechanisms of segregation, phase separation and self-assembly.
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Affiliation(s)
- Pedro Morgado
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
| | - João Barras
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
| | - Eduardo J M Filipe
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
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15
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Morgado P, Colaço B, Santos V, Jackson G, Filipe EJM. Modelling the thermodynamic properties and fluid-phase equilibria of n-perfluoroalkanes and their binary mixtures with the SAFT- γ Mie group contribution equation of state. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1722270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Pedro Morgado
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Beatriz Colaço
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Vera Santos
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
- Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, London, UK
| | - George Jackson
- Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, London, UK
| | - Eduardo J. M. Filipe
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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16
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Tasche J, Sabattié EFD, Thompson RL, Campana M, Wilson MR. Oligomer/Polymer Blend Phase Diagram and Surface Concentration Profiles for Squalane/Polybutadiene: Experimental Measurements and Predictions from SAFT-γ Mie and Molecular Dynamics Simulations. Macromolecules 2020; 53:2299-2309. [PMID: 32308214 PMCID: PMC7161083 DOI: 10.1021/acs.macromol.9b02155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/12/2020] [Indexed: 01/16/2023]
Abstract
The compatibility and surface behavior of squalane-polybutadiene mixtures are studied by experimental cloud point and neutron reflectivity measurements, statistical associating fluid theory (SAFT), and molecular dynamics (MD) simulations. A SAFT-γ Mie model is shown to be successful in capturing the cloud point curves of squalane-polybutadiene and squalane-cis-polybutadiene binary mixtures, and the same SAFT-γ Mie model is used to develop a thermodynamically consistent top-down coarse-grained force field to describe squalane-polybutadiene. Coarse-grained molecular dynamics simulations are performed to study surface behavior for different concentrations of squalane, with the system exhibiting surface enrichment and a wetting transition. Simulated surface profiles are compared with those obtained by fitting to neutron reflectivity data obtained from thin films composed of deuterated squalane (d-sq)-polybutadiene. The presented top-down parametrization methodology is a fast and thermodynamically reliable approach for predicting properties of oligomer-polymer mixtures, which can be challenging for either theory or MD simulations alone.
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Affiliation(s)
- Jos Tasche
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, United Kingdom
| | - Elise F D Sabattié
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, United Kingdom
| | - Richard L Thompson
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, United Kingdom
| | - Mario Campana
- Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom
| | - Mark R Wilson
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, United Kingdom
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17
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Silva GM, Justino J, Morgado P, Teixeira M, Pereira LM, Vega LF, Filipe EJ. Detailed surface characterization of highly fluorinated liquid alcohols: Experimental surface tensions, molecular simulations and soft-SAFT theory. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112294] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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18
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Walker CC, Genzer J, Santiso EE. Extending the fused-sphere SAFT-γ Mie force field parameterization approach to poly(vinyl butyral) copolymers. J Chem Phys 2020; 152:044903. [DOI: 10.1063/1.5126213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Christopher C. Walker
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Jan Genzer
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Erik E. Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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19
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Theodorakis PE, Smith ER, Müller EA. Spreading of aqueous droplets with common and superspreading surfactants. A molecular dynamics study. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.123810] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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Molecular Dynamics Simulation of the Superspreading of Surfactant-Laden Droplets. A Review. FLUIDS 2019. [DOI: 10.3390/fluids4040176] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Superspreading is the rapid and complete spreading of surfactant-laden droplets on hydrophobic substrates. This phenomenon has been studied for many decades by experiment, theory, and simulation, but it has been only recently that molecular-level simulation has provided significant insights into the underlying mechanisms of superspreading thanks to the development of accurate force-fields and the increase of computational capabilities. Here, we review the main advances in this area that have surfaced from Molecular Dynamics simulation of all-atom and coarse-grained models highlighting and contrasting the main results and discussing various elements of the proposed mechanisms for superspreading. We anticipate that this review will stimulate further research on the interpretation of experimental results and the design of surfactants for applications requiring efficient spreading, such as coating technology.
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21
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Pervaje AK, Walker CC, Santiso EE. Molecular simulation of polymers with a SAFT-γ Mie approach. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1645331] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Amulya K. Pervaje
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Christopher C. Walker
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Erik E. Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
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22
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Spontaneous self-assembly and structure of perfluoroalkylalkane surfactant hemimicelles by molecular dynamics simulations. Proc Natl Acad Sci U S A 2019; 116:14868-14873. [PMID: 31278150 DOI: 10.1073/pnas.1906782116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fully atomistic molecular-dynamics (MD) simulations of perfluoroalkylalkane molecules at the surface of water show the spontaneous formation of aggregates whose size and topography closely resemble the experimentally observed hemimicelles for this system. Furthermore, the grazing incidence X-ray diffraction (GIXD) pattern calculated from the simulation trajectories reproduces the experimental GIXD spectra previously obtained, fully validating the MD simulation results. The detailed analysis of the internal structure of the aggregates obtained by the MD simulations supports a definite rational explanation for the spontaneous formation, stability, size, and shape of perfluoroalkylalkane hemimicelles at the surface of water.
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23
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Crespo EA, Coutinho JAP. A Statistical Associating Fluid Theory Perspective of the Modeling of Compounds Containing Ethylene Oxide Groups. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00273] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Emanuel A. Crespo
- CICECO − Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - João A. P. Coutinho
- CICECO − Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
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24
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Walker CC, Genzer J, Santiso EE. Development of a fused-sphere SAFT-γ Mie force field for poly(vinyl alcohol) and poly(ethylene). J Chem Phys 2019; 150:034901. [DOI: 10.1063/1.5078742] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Christopher C. Walker
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Jan Genzer
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Erik E. Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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25
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Pervaje AK, Tilly JC, Inglefield DL, Spontak RJ, Khan SA, Santiso EE. Modeling Polymer Glass Transition Properties from Empirical Monomer Data with the SAFT-γ Mie Force Field. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01734] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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26
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Rahman S, Lobanova O, Jiménez-Serratos G, Braga C, Raptis V, Müller EA, Jackson G, Avendaño C, Galindo A. SAFT-γ Force Field for the Simulation of Molecular Fluids. 5. Hetero-Group Coarse-Grained Models of Linear Alkanes and the Importance of Intramolecular Interactions. J Phys Chem B 2018; 122:9161-9177. [DOI: 10.1021/acs.jpcb.8b04095] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sadia Rahman
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Olga Lobanova
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Guadalupe Jiménez-Serratos
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Carlos Braga
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Vasilios Raptis
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Erich A. Müller
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - George Jackson
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Carlos Avendaño
- School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Amparo Galindo
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
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27
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Affiliation(s)
- Frederike Jaeger
- Department of Physics, Imperial College London, London SW7 2AZ, United Kingdom
| | - Omar K. Matar
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Erich A. Müller
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
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28
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Vlasiuk M, Sadus RJ. Ab initio interatomic potentials and the thermodynamic properties of fluids. J Chem Phys 2017; 147:024505. [DOI: 10.1063/1.4991012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Jiménez-Serratos G, Herdes C, Haslam AJ, Jackson G, Müller EA. Group Contribution Coarse-Grained Molecular Simulations of Polystyrene Melts and Polystyrene Solutions in Alkanes Using the SAFT-γ Force Field. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02072] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Carmelo Herdes
- Department
of Chemical Engineering, University of Bath, Bath BA2 7AY, U.K
| | - Andrew J. Haslam
- Department
of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - George Jackson
- Department
of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Erich A. Müller
- Department
of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
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