Non-equilibrium molecular dynamics simulations of organic friction modifiers
|
|
- Lorin Bryan
- 6 years ago
- Views:
Transcription
1 Non-equilibrium molecular dynamics simulations of organic friction modifiers James Ewen PhD Student Tribology Group (Shell UTC) Imperial College London Session 8B Bronze 2 Lubrication Fundamentals STLE Annual Meeting 19 th May 2016
2 Contents 1. Introduction: a) Molecular Dynamics (MD) in tribology b) Organic Friction Modifiers c) Research objectives 2. Methodology: a) Simulation procedure b) Force-Fields 3. Results: a) Preliminary squeeze out simulations b) Film structure c) Friction coefficient d) AA vs. UA 4. Conclusions
3 Time Scale Static 1ps 1ns 1μs 1ms 1. Introduction a) Molecular Dynamics (MD) in tribology Classical MD is the cheapest atomic scale simulation method Length Scale 0.1nm 1nm 10nm >1μm But no reactivity information (electrons not treated explicitly) In tribology, MD gives unique insight into:» Nanoscale structure of lubricant and additive molecule systems» Complex friction behaviour Coarse Graining Atomistic MD QM/MM Continuum (e.g. CFD)» Important tribological phenomena (e.g. shear thinning, stick-slip) QMC DFT Number of Atoms Fig 1: Computational Simulation Methods - adapted from: Kermode et al., Multiscale Simulation Methods in Molecular Sciences, NIC Series, Vol 42, (2009)
4 1. Introduction a) Organic Friction Modifiers (OFMs) Boundary Lubrication (low sliding speed/high pressure) high friction Polar Head Group Fatty Tail Hardy Model Fig 2. Generalised Stribeck Curve OFM polar head groups adsorb onto surface Form monolayer interchain Van Der Waals forces between fatty tails Incompressible and prevents solid-solid contact reduces friction Fig 3. Schematic of action of model organic friction modifiers Stachowiak & Batchelor, Engineering Tribology, Elsevier Inc., 2005
5 1. Introduction a) Research objectives Confined NEMD simulations of OFMs Gain unique insight into: Nanoscale film structure Friction reduction mechanism Relative performance of different OFMs Comparative studies, different: Tail groups (Z-unsaturation) Head groups (acid, amide, glyceride) Surface coverages Conditions sliding velocity, pressure Force-fields AA vs. UA
6 2. Methodology a) Simulation procedure 55 A Three OFM coverages: 4.32, 2.88, 1.44 nm -2 (max = 4.55 nm -2 ) OFM Film Hexadecane OFM Film Fig 4. (a) NEMD system set up, (b) OFM molecules simulated Surface (100) α-fe 2 O 3 (hematite) harmonic potential (Berro 2010) Surface-OFM, Surface-Lubricant Lennard-Jones and Coulombic potentials Lubricant and OFM molecules (L-)OPLS All-Atom (Jorgensen 1996, Price 2001, Siu 2012)
7 2. Methodology a) Force-Fields V total = V stretch + V bend + V torsion + V VDW + V qq V VDW (r ij ) = 4ε ij σ ij r ij 12 σ ij r ij 6 V qq r ij = q iq j 4πε r r ij 2 Fig 5. Potentials included in classical empirically parameterised Force-Field Fig 6. a) All-Atom and b) United-Atom force-field representation of n-hexadecane
8 a) Preliminary squeeze out simulations Estimate hexadecane layer thickness at 0.5 GPa Fig 7. Variation in; (a) wall separation, (b) number of hexadecane molecules inside contact, with time Vacuum added in x-y plane to allow hexadecane to be squeezed out (Sivebaek 2003) Decreasing wall separation converges at equilibrium value Equilibrium wall separation increases with OFM coverage Equilibrium amount of hexadecane remaining inside contact volume independent on OFM coverage (two layers)
9 b) Film structure - NEMD videos SA High (4.32 nm -2 ) 0.5 GPa, 10m/s SA Medium (2.88 nm -2 ) High coverage solid-like films with well-separated confined hexadecane layer Medium coverage amorphous films which are significantly interdigitated Molecular tilt partially aligns with the sliding direction NEMD can gain unique insight into structure and friction of OFM the films
10 b) Film structure OFM z CoM and tilt angle Higher coverage larger z-com Fig 8. Variation in; (a) z CoM, (b) tilt angle, with OFM coverage Higher coverage lower tilt angle Saturated and unsaturated tail-groups similar z-extension GMS & GMO larger z-extension most significant at high coverage Tilt angle relatively independent of head and tail group type Good agreement with SFA and in-situ AFM experiments (Campen 2015)
11 b) Film structure atomic mass density profiles 4.32 nm nm nm -2 Layering of additive and lubricant in z More interdigitation of lubricant into OFM film at lower coverage More interdigitation of lubricant into OFM film in acids than glycerides Glyceride films slightly thicker than acid Good agreement with SFA and in-situ AFM Fig 9. Atomic Mass Density Profiles for: (a) GMS/GMO (b) SA/OA Z-unsaturated tail group similar structure
12 b) Film structure RDF and intermolecular hydrogen bonding 4.32 nm nm nm -2 C C CTT CTT Fig 10. RDF for SA and GMS at high, medium and low coverage Higher coverage more solid-like film (increased long-range order) Glyceride (green) more solid-like than acid (orange) Intermolecular hydrogen bonding (3 vs 1 HB per OFM) Explanation for lower interdigitation for glycerides films
13 b) Film structure Velocity Profiles 4.32 nm nm nm -2 Fig 11. Velocity profile for SA at high, medium and low coverage High coverage: OFM molecules move with wall, clear slip planes between OFM-hexadecane and hexadecane-hexadecane layers Medium coverage: slip plane less clear viscous friction in interdigitated region Low coverage: more Couette-like velocity profile similar to confined pure hexadecane (Savio 2013)
14 c) Friction coefficient effect of OFM coverage 0.5 GPa, 10m/s 4.32 nm nm nm -2 Solid Amorphous (Yoshizawa 1992) Liquid Fig 12. Variation in friction coefficient with coverage High coverage: low friction formation of solid-like film, interdigitation low, facilitates slip plane between layers Medium coverage: high friction interdigitation high, rearrangement slow Low coverage: intermediate friction films more interdigitated, rearrangement fast Friction coefficient: OA SA > OAm SAm GMO > GMS (Campen 2012)
15 c) Friction coefficient effect of sliding velocity 4.32 nm nm nm -2 Fig 13. Variation in friction coefficient with sliding velocity at high, medium and low coverage Friction increases linearly with logarithm of sliding velocity Predicted by shear-induced thermal activation theory (Briscoe 1982, He 2001) Observed experimentally for boundary friction of OFM films (Campen 2012) Medium coverage friction greater dependence on sliding velocity Experimental behaviour: saturated (high coverage) vs. Z-unsaturated (low coverage)
16 d) AA vs. UA Viscosity? Film Structure? Film Phase? Friction? Compare SA film structure and friction results for AA vs. UA force-fields: 1. (L-)OPLS All-Atom (Jorgensen 1996, Price 2001, Siu 2012) 2. TraPPE United-Atom (Martin 1998, Clifford 2006) UA order of magnitude cheaper lower sliding velocities accessible But UA known to under-predict viscosity of long-chain alkanes (Allen 1997)
17 d) AA vs. UA effect of OFM coverage UA accurately represents OFM film structure, however: UA much lower friction coefficient than AA AA friction-coverage behaviour agrees with experiment (Yoshizawa 1993) UA friction-coverage behaviour opposite of experimental trend For UA, interdigitation much less critical to friction AA model necessary for accurate simulations of OFM friction Fig 14. Variation in SA friction coefficient with coverage UA vs AA
18 d) AA vs. UA effect of sliding velocity 4.32 nm nm -2 Fig 15. Variation in friction coefficient with sliding velocity UA vs AA UA much lower friction coefficient at all speeds and coverages Larger difference between AA and UA at medium coverage - more interdigitation UA also captures logarithmic trend, but values well below experiments
19 d) AA vs. UA experimental comparisons Experimental (Campen 2012) NEMD (high coverage) Stearic acid AA Stearic acid UA 1E-01 1E-00 1E+01 1E+02 (1ms -1 ) (10ms -1 ) Fig 15. Variation in friction coefficient with logarithm of sliding velocity UA vs AA LHS experimental (Campen 2012), RHS high coverage NEMD results Experimental friction coefficients agree much better with AA simulations Further suggests that AA models necessary for OFM simulations
20 4. Conclusions Constructed model to compare various OFMs under different conditions Film structure varies significantly depending on OFM type and coverage Substantial reduction in friction at high coverage - slip plane Z-unsaturated OFMs equally low CoF to saturated ones experimental differences due to lower coverage GMS outperforms other OFMs at all coverages (H-bonding) Friction coefficient increases with logarithm of sliding velocity AA force-fields critical to accurately model OFM friction behaviour Ewen, J., Gattinoni, C., Morgan, N., Spikes, H., Dini, D. Non-equilibrium molecular dynamics simulations of organic friction modifiers adsorbed on iron oxide surfaces, Langmuir, 2016
21 Acknowledgements Research funded by the EPSRC and Shell (CASE) Many thanks to: Dr. D. Dini, Prof. H. Spikes, Prof. D. Heyes, Dr. C. Gattinoni (Imperial), Dr. N. Morgan (Shell) and the computational chemistry group at Shell India Private Markets Limited All systems were constructed using the MAPS platform by Scienomics Inc., simulations were run in LAMMPS and visualisations were created using VMD.
22 References Allen 1997 Allen, W., Rowley, R. L, Predicting the viscosity of alkanes using nonequilibrium molecular dynamics: Evaluation of intermolecular potential models. J. Chem. Phys. (1997) Berro 2010 Molecular dynamics simulation of surface energy and ZDDP effects on friction in nano-scale lubricated contacts. Tribol. Int. (2010) Briscoe 1982 Briscoe, B. J.; Evans, D. C. B. The shear properties of Langmuir-Blodgett layers. Proc. R. Soc. A (1982) Campen 2012 Campen, S., Green, J., Lamb, G., Atkinson, D., Spikes, H. On the Increase in Boundary Friction with Sliding Speed. Tribol. Lett. (2012) Campen 2015 Campen, S.; Green, J. H.; Lamb, G. D.; Spikes, H. A. In Situ Study of Model Organic Friction Modifiers Using Liquid Cell AFM; Saturated and Mono-unsaturated Carboxylic Acids. Tribol. Lett. (2015) Clifford 2006 Clifford, S., Bolton, K., Ramjugernath, D., Monte Carlo simulation of carboxylic acid phase equilibria, J. Phys. Chem. B (2006) He 2001 He, G.; Robbins, M. O. Simulations of the kinetic friction due to adsorbed surface layers. Tribol. Lett. (2001) Jorgensen 1996 Jorgensen, W.L., Maxwell, D.S., Tirado-Rives, J. Development and testing of the OPLS all-atom force field on conformational energetics and properties of organic liquids. J. Am. Chem. Soc. (1996) Martin 1997 Martin, M.G., Siepmann, J.I. Transferable potentials for phase equilibria. 1. United-atom description of n-alkanes. J. Phys. Chem. B (1998). Price 2001 Price, D.J., Brooks, C.L. Modern protein force fields behave comparably in molecular dynamics simulations. J. Comput. Chem. (2002) Savio 2013 Savio, D.; Fillot, N.; Vergne, P. A Molecular Dynamics Study of the Transition from Ultra-Thin Film Lubrication Toward Local Film Breakdown. Tribol. Lett. (2013) Siu 2012 Siu, S.W.I., Pluhackova, K., Bockmann, R.A. Optimization of the OPLS-AA Force Field for Long Hydrocarbons. J. Chem. Theory Comput. (2012) Sivebaek 2003 Sivebaek, I. M.; Samoilov, V. N.; Persson, B. N. J. Squeezing molecular thin alkane lubrication films between curved solid surfaces with longrange elasticity: Layering transitions and wear. J. Chem. Phys. (2003) Yoshizawa 1993 Yoshizawa, H.; Chen, Y. L.; Israelachvili, J. Fundamental mechanisms of interfacial friction: 1. relation between adhesion and friction. J. Phys. Chem. (1993)
MOLECULAR DYNAMICS SIMULATIONS OF FRICTION FORCE VERSUS LOAD
MOLECULAR DYNAMICS SIMULATIONS OF FRICTION FORCE VERSUS LOAD Ana-Camelia Pirghie Stefan cel Mare University of Suceava, Department of Mechanics and Technology, camelia.pirghie@fim.usv.ro Abstract: The
More informationSlip of Alkanes Confined between Surfactant Monolayers Adsorbed on Solid Surfaces
This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source
More informationarxiv: v1 [cond-mat.mtrl-sci] 24 Jan 2012
Effective Viscosity of Confined Hydrocarbons I.M. Sivebaek,2,3, V.N. Samoilov,4 and B.N.J. Persson IFF, FZ-Jülich, 52425 Jülich, Germany 2 Novo Nordisk A/S, Research and Development, DK4 Hillerod, Denmark
More informationVelocity Dependence of Friction of Confined Hydrocarbons
pubs.acs.org/langmuir 2010 American Chemical Society Velocity Dependence of Friction of Confined Hydrocarbons Ion M. Sivebaek,*,,, Vladimir N. Samoilov,,^ and Bo N. J. Persson IFF, FZ-J ulich, 52425 J
More informationNanorheology of liquid alkanes
Ž. Fluid Phase Equilibria 150 151 1998 125 131 Nanorheology of liquid alkanes S.A. Gupta a,b, H.D. Cochran a,b, P.T. Cummings a,b,) a Department of Chemical Engineering, UniÕersity of Tennessee, KnoxÕille,
More informationStructural and Mechanical Properties of Nanostructures
Master s in nanoscience Nanostructural properties Mechanical properties Structural and Mechanical Properties of Nanostructures Prof. Angel Rubio Dr. Letizia Chiodo Dpto. Fisica de Materiales, Facultad
More informationThe Effect of Model Internal Flexibility Upon NEMD Simulations of Viscosity
Draft: September 29, 1999 The Effect of Model Internal Flexibility Upon NEMD Simulations of Viscosity N. G. Fuller 1 and R. L. Rowley 1,2 Abstract The influence of model flexibility upon simulated viscosity
More informationCE 530 Molecular Simulation
1 CE 530 Molecular Simulation Lecture 1 David A. Kofke Department of Chemical Engineering SUNY Buffalo kofke@eng.buffalo.edu 2 Time/s Multi-Scale Modeling Based on SDSC Blue Horizon (SP3) 1.728 Tflops
More informationStructural Bioinformatics (C3210) Molecular Mechanics
Structural Bioinformatics (C3210) Molecular Mechanics How to Calculate Energies Calculation of molecular energies is of key importance in protein folding, molecular modelling etc. There are two main computational
More informationInterfacial forces and friction on the nanometer scale: A tutorial
Interfacial forces and friction on the nanometer scale: A tutorial M. Ruths Department of Chemistry University of Massachusetts Lowell Presented at the Nanotribology Tutorial/Panel Session, STLE/ASME International
More informationk θ (θ θ 0 ) 2 angles r i j r i j
1 Force fields 1.1 Introduction The term force field is slightly misleading, since it refers to the parameters of the potential used to calculate the forces (via gradient) in molecular dynamics simulations.
More informationAvailable online at ScienceDirect. Procedia Engineering 79 (2014 )
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 79 (2014 ) 617 621 CTAM 2013 The 37 th National Conference on Theoretical and Applied Mechanics (37th-NCTAM) The 1 st International
More informationNanotribology of Symmetric and Asymmetric Liquid Lubricants
Symmetry 2010, 2, 320-345; doi:10.3390/sym2010320 OPEN ACCESS symmetry ISSN 2073-8994 www.mdpi.com/journal/symmetry Review Nanotribology of Symmetric and Asymmetric Liquid Lubricants Shinji Yamada Tokyo
More informationMolecular Dynamics Simulation of a Nanoconfined Water Film
Molecular Dynamics Simulation of a Nanoconfined Water Film Kyle Lindquist, Shu-Han Chao May 7, 2013 1 Introduction The behavior of water confined in nano-scale environment is of interest in many applications.
More informationAtomic scale friction in the function of modified Eyring activation energies
Loughborough University Institutional Repository Atomic scale friction in the function of modified Eyring activation energies This item was submitted to Loughborough University's Institutional Repository
More informationCE 530 Molecular Simulation
1 CE 530 Molecular Simulation Lecture 14 Molecular Models David A. Kofke Department of Chemical Engineering SUNY Buffalo kofke@eng.buffalo.edu 2 Review Monte Carlo ensemble averaging, no dynamics easy
More informationIntroduction to molecular dynamics
1 Introduction to molecular dynamics Yves Lansac Université François Rabelais, Tours, France Visiting MSE, GIST for the summer Molecular Simulation 2 Molecular simulation is a computational experiment.
More informationNon-equilibrium molecular dynamics simulation study of the behavior of hydrocarbon-isomers in silicalite
Fluid Phase Equilibria 194 197 (2002) 309 317 Non-equilibrium molecular dynamics simulation study of the behavior of hydrocarbon-isomers in silicalite S. Furukawa a,b,, C. McCabe a,c, T. Nitta b, P.T.
More informationSliding Friction in the Frenkel-Kontorova Model
arxiv:cond-mat/9510058v1 12 Oct 1995 to appear in "The Physics of Sliding Friction", Ed. B.N.J. Persson (Kluwer Academic Publishers), 1995 Sliding Friction in the Frenkel-Kontorova Model E. Granato I.N.P.E.,
More informationDepartment of Engineering Mechanics, SVL, Xi an Jiaotong University, Xi an
The statistical characteristics of static friction J. Wang, G. F. Wang*, and W. K. Yuan Department of Engineering Mechanics, SVL, Xi an Jiaotong University, Xi an 710049, China * E-mail: wanggf@mail.xjtu.edu.cn
More informationThe Molecular Dynamics Method
The Molecular Dynamics Method Thermal motion of a lipid bilayer Water permeation through channels Selective sugar transport Potential Energy (hyper)surface What is Force? Energy U(x) F = d dx U(x) Conformation
More informationStructural transition and solid-like behavior of alkane films confined in nano-spacing
Fluid Phase Equilibria 183 184 (2001) 381 387 Structural transition and solid-like behavior of alkane films confined in nano-spacing S.T. Cui a,b,, P.T. Cummings b,c, H.D. Cochran a,b a Department of Chemical
More informationPHYSICAL CHEMISTRY THE JOURNAL OF CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES, & BIOPHYSICAL CHEMISTRY
JPCBFK VOLUME 108 MARCH 18, 2004 NUMBER 11 http://pubs.acs.org/jpcb THE JOURNAL OF PHYSICAL CHEMISTRY B Simulated Hexadecane Molecules Confined by Atomically Rough Gold Surfaces Exhibiting Amontons' Friction
More informationGlobal Optimisation of Hydrated Sulfate Clusters
Global Optimisation of Hydrated Sulfate Clusters Lewis Smeeton University of Birmingham School of Chemistry 15 th December, 2014 1 / 31 1 Introduction The Hofmeister Series Hydrated Sulfate Clusters 2
More informationQuantized Friction across Ionic Liquid Thin Films
Quantized Friction across Ionic Liquid Thin Films Alexander M. Smith 1, Kevin R. J. Lovelock 2, Nitya Nand Gosvami 3, Tom Welton 2, and Susan Perkin 1 * Affiliations: 1 Department of Chemistry, Physical
More informationSupporting Information
Projection of atomistic simulation data for the dynamics of entangled polymers onto the tube theory: Calculation of the segment survival probability function and comparison with modern tube models Pavlos
More informationA General Equation for Fitting Contact Area and Friction vs Load Measurements
Journal of Colloid and Interface Science 211, 395 400 (1999) Article ID jcis.1998.6027, available online at http://www.idealibrary.com on A General Equation for Fitting Contact Area and Friction vs Load
More informationarxiv: v1 [cond-mat.stat-mech] 6 Jan 2014
arxiv:1401.1181v1 [cond-mat.stat-mech] 6 Jan 2014 Determination of Forces from a Potential in Molecular Dynamics (note) Bernard Monasse Mines-ParisTech, Cemef bernard.monasse@mines-paristech.fr January
More informationSpecific ion effects on the interaction of. hydrophobic and hydrophilic self assembled
Supporting Information Specific ion effects on the interaction of hydrophobic and hydrophilic self assembled monolayers T. Rios-Carvajal*, N. R. Pedersen, N. Bovet, S.L.S. Stipp, T. Hassenkam. Nano-Science
More informationNanotribology. Judith A. Harrison & Ginger M. Chateauneuf. Chemistry Department United States Naval Academy Annapolis, MD
Nanotribology Judith A. Harrison & Ginger M. Chateauneuf Chemistry Department United States Naval Academy Annapolis, MD 140 jah@usna.edu Some Reviews 1. J. A. Harrison et al, Atomic-Scale Simulation of
More informationA Molecular Dynamics Simulation of a Homogeneous Organic-Inorganic Hybrid Silica Membrane
A Molecular Dynamics Simulation of a Homogeneous Organic-Inorganic Hybrid Silica Membrane Supplementary Information: Simulation Procedure and Physical Property Analysis Simulation Procedure The molecular
More informationPolypeptide Folding Using Monte Carlo Sampling, Concerted Rotation, and Continuum Solvation
Polypeptide Folding Using Monte Carlo Sampling, Concerted Rotation, and Continuum Solvation Jakob P. Ulmschneider and William L. Jorgensen J.A.C.S. 2004, 126, 1849-1857 Presented by Laura L. Thomas and
More informationOleg A. Mazyar, Guoai Pan and Clare McCabe*
Molecular Physics Vol. 107, No. 14, 20 July 2009, 1423 1429 RESEARCH ARTICLE Transient time correlation function calculation of the viscosity of a molecular fluid at low shear rates: a comparison of stress
More informationThermodynamic behaviour of mixtures containing CO 2. A molecular simulation study
Thermodynamic behaviour of mixtures containing. A molecular simulation study V. Lachet, C. Nieto-Draghi, B. Creton (IFPEN) Å. Ervik, G. Skaugen, Ø. Wilhelmsen, M. Hammer (SINTEF) Introduction quality issues
More informationA multiscale framework for lubrication analysis of bearings with textured surface
A multiscale framework for lubrication analysis of bearings with textured surface *Leiming Gao 1), Gregory de Boer 2) and Rob Hewson 3) 1), 3) Aeronautics Department, Imperial College London, London, SW7
More informationStick and Slip Behaviour of Confined Oligomer Melts under Shear. A Molecular-Dynamics Study.
EUROPHYSICS LETTERS Europhys. Lett., 24 (2), pp. 99-104 (1993) 10 October 1993 Stick and Slip Behaviour of Confined Oligomer Melts under Shear. A Molecular-Dynamics Study. E. MANIAS(*), G. HADZIIOANNOU(*),
More informationA Nonequilibrium Molecular Dynamics Study of. the Rheology of Alkanes. S.A. Gupta, S. T. Cui, P. T. Cummings and H. D. Cochran
A Nonequilibrium Molecular Dynamics Study of the Rheology of Alkanes S.A. Gupta, S. T. Cui, P. T. Cummings and H. D. Cochran Department of Chemical Engineering University of Tennessee Knoxville, TN 37996-2200
More informationMolecular dynamics simulations of friction between alkylsilane monolayers
INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 14 (2006) 283 297 doi:10.1088/0965-0393/14/2/011 Molecular dynamics simulations
More informationNotes on Rubber Friction
Notes on Rubber Friction 2011 A G Plint Laws of Friction: In dry sliding between a given pair of materials under steady conditions, the coefficient of friction may be almost constant. This is the basis
More informationIndentation of Silicon: Phase Transition? Indentation of Silicon: Phase Transition?
Indentation of Silicon: Phase Transition? Kallman et al., Phys. Rev. B. 47, 7705 (1993). Smith et al., Acta. Mater. 49, 4089 (2001). MD: NVT 350,000 atoms Cut away of crystalline Si indented with a tetrahedral
More informationMolecular dynamics simulation of nanofluidics and nanomachining
Molecular dynamics simulation of nanofluidics and nanomachining M. T. Horsch,1, 4 S. Stephan,1 S. Becker,1 M. Heier,1 M. P. Lautenschläger,1 F. Diewald,2 R. Müller,2 H. M. Urbassek,3 and H. Hasse1 1 Engineering
More informationAdvances in nonequilibrium molecular dynamics simulations of lubricants and additives
Friction ISSN 2223-7690 https://doi.org/10.1007/s40544-018-0207-9 CN 10-1237/TH REVIEW ARTICLE Advances in nonequilibrium molecular dynamics simulations of lubricants and additives J. P. EWEN, D. M. HEYES,
More informationMD simulation of methane in nanochannels
MD simulation of methane in nanochannels COCIM, Arica, Chile M. Horsch, M. Heitzig, and J. Vrabec University of Stuttgart November 6, 2008 Scope and structure Molecular model for graphite and the fluid-wall
More informationMolecular Thermodynamics of Adsorption Using a 2D- SAFT-VR-Mie Approach
Molecular Thermodynamics of Adsorption Using a 2D- SAFT-VR-Mie Approach Gerardo Campos, Jonatan Suaste, Andrew Haslam, George Jackson and Alejandro Gil-Villegas Outline Adsorption Statistical Associating
More informationSupplementary Information for: Controlling Cellular Uptake of Nanoparticles with ph-sensitive Polymers
Supplementary Information for: Controlling Cellular Uptake of Nanoparticles with ph-sensitive Polymers Hong-ming Ding 1 & Yu-qiang Ma 1,2, 1 National Laboratory of Solid State Microstructures and Department
More informationNonequilibrium Molecular Dynamics Simulations of Shear Viscosity: Isoamyl Alcohol, n-butyl Acetate and Their Mixtures
Draft Date: October 5, 1999 Nonequilibrium Molecular Dynamics Simulations of Shear Viscosity: Isoamyl Alcohol, n-butyl Acetate and Their Mixtures Y. Yang 1, T. A. Pakkanen, 2 and R. L. Rowley 1,3 Draft
More informationSupporting Information for Solid-liquid Thermal Transport and its Relationship with Wettability and the Interfacial Liquid Structure
Supporting Information for Solid-liquid Thermal Transport and its Relationship with Wettability and the Interfacial Liquid Structure Bladimir Ramos-Alvarado, Satish Kumar, and G. P. Peterson The George
More informationMechanical Interactions at the Interfaces of Atomically Thin Materials (Graphene)
Mechanical Interactions at the Interfaces of Atomically Thin Materials (Graphene) Rui Huang Center for Mechanics of Solids, Structures and Materials Department of Aerospace Engineering and Engineering
More informationUniversal Repulsive Contribution to the. Solvent-Induced Interaction Between Sizable, Curved Hydrophobes: Supporting Information
Universal Repulsive Contribution to the Solvent-Induced Interaction Between Sizable, Curved Hydrophobes: Supporting Information B. Shadrack Jabes, Dusan Bratko, and Alenka Luzar Department of Chemistry,
More informationEarly stages of dewetting of microscopically thin polymer films: A molecular dynamics study
JOURNAL OF CHEMICAL PHYSICS VOLUME 109, NUMBER 19 15 NOVEMBER 1998 Early stages of dewetting of microscopically thin polymer films: A molecular dynamics study Hong Liu Department of Physics, Kansas State
More informationTRIBOLOGY OF DIAMOND AND SILICON
TRIBOLOGY OF DIAMOND AND SILICON ATOMIC-SCALE INSIGHTS FROM COMPUTER SIMULATIONS University of Warwick WCPM Seminars 19.02.2018 Gianpietro Moras Fraunhofer lines gianpietro.moras@iwm.fraunhofer.de Contract
More informationMOLECULAR DYNAMICS SIMULATION ON TOTAL THERMAL RESISTANCE OF NANO TRIANGULAR PIPE
ISTP-16, 2005, PRAGUE 16 TH INTERNATIONAL SYMPOSIUM ON TRANSPORT PHENOMENA MOLECULAR DYNAMICS SIMULATION ON TOTAL THERMAL RESISTANCE OF NANO TRIANGULAR PIPE C.S. Wang* J.S. Chen* and S. Maruyama** * Department
More informationNumerical modeling of sliding contact
Numerical modeling of sliding contact J.F. Molinari 1) Atomistic modeling of sliding contact; P. Spijker, G. Anciaux 2) Continuum modeling; D. Kammer, V. Yastrebov, P. Spijker pj ICTP/FANAS Conference
More informationFree Radical-Initiated Unfolding of Peptide Secondary Structure Elements
Free Radical-Initiated Unfolding of Peptide Secondary Structure Elements Thesis of the Ph.D. Dissertation by Michael C. Owen, M.Sc. Department of Chemical Informatics Faculty of Education University of
More informationSelf assembly of Carbon Atoms in Interstellar Space and Formation Mechanism of Naphthalene from Small Precursors: A Molecular Dynamics Study
Self assembly of Carbon Atoms in Interstellar Space and Formation Mechanism of Naphthalene from Small Precursors: A Molecular Dynamics Study Niladri Patra UIC Advisor: Dr. H. R. Sadeghpour ITAMP Large
More informationStick-slip motion in boundary lubrication
Stick-slip motion in boundary lubrication Abstract Silang Zhou Supervisor: Dr. Antonis Vakis & Soheil Solhjoo With the development of the surface force apparatus (SFA) and molecular dynamics (MD) simulations,
More informationHow Lubricants Work. If a protective film were present on each of the surfaces, the surfaces could be separated:
How Lubricants Work An understanding of how lubricating systems work is crucial to the selection of a lubricant for a particular application. This essay could be summarized in one sentence: lubricants
More informationReactive Empirical Force Fields
Reactive Empirical Force Fields Jason Quenneville jasonq@lanl.gov X-1: Solid Mechanics, EOS and Materials Properties Applied Physics Division Los Alamos National Laboratory Timothy C. Germann, Los Alamos
More informationMicroscopic study of thin film lubrication and its contributions to macroscopic tribology
Tribology Letters 5 (1998) 81 88 81 Microscopic study of thin film lubrication and its contributions to macroscopic tribology Yuan-Zhong Hu a, and Steve Granick b a National Tribology Laboratory, Tsinghua
More informationDeformation and tribology of multi-walled hollow nanoparticles
arxiv:cond-mat/0005017v1 [cond-mat.mtrl-sci] 1 May 2000 Deformation and tribology of multi-walled hollow nanoparticles U. S. Schwarz, S. Komura and S. A. Safran Department of Materials and Interfaces,
More informationThe current status of tribological surface science
Tribology Letters Vol. 10, No. 1-2, 2001 39 The current status of tribological surface science Andrew J. Gellman and Jeff S. Ko Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh,
More informationBiomolecules are dynamic no single structure is a perfect model
Molecular Dynamics Simulations of Biomolecules References: A. R. Leach Molecular Modeling Principles and Applications Prentice Hall, 2001. M. P. Allen and D. J. Tildesley "Computer Simulation of Liquids",
More informationSupporting Information
Supporting Information Ionic Liquid Designed for PEDOT:PSS Conductivity Enhancement Ambroise de Izarra, a,b,1 Seongjin Park, a,1 Jinhee Lee, a Yves Lansac, b,c, * Yun Hee Jang a, * a Department of Energy
More informationContents. Preface XI Symbols and Abbreviations XIII. 1 Introduction 1
V Contents Preface XI Symbols and Abbreviations XIII 1 Introduction 1 2 Van der Waals Forces 5 2.1 Van der Waals Forces Between Molecules 5 2.1.1 Coulomb Interaction 5 2.1.2 Monopole Dipole Interaction
More informationImpact of molecular structure on the lubricant squeeze-out between curved surfaces with long range elasticity
Downloaded from orbit.dtu.dk on: Jan 30, 2019 Impact of molecular structure on the lubricant squeeze-out between curved surfaces with long range elasticity Tartaglino, Ugo; Sivebæk, Ion Marius; Persson,
More informationPredicting the viscosity of alkanes using nonequilibrium molecular dynamics: Evaluation of intermolecular potential models
Brigham Young University BYU ScholarsArchive All Faculty Publications 1997-06-22 Predicting the viscosity of alkanes using nonequilibrium molecular dynamics: Evaluation of intermolecular potential models
More informationLecture 11 Friction Lubrication, and Wear
Lecture 11 Friction, Lubrication and Wear Definitions Friction force between the interacting surfaces that resists or hinders their relative movement Static friction force to overcome to start movement
More informationTheoretical comparative study on hydrogen storage of BC 3 and carbon nanotubes
J. At. Mol. Sci. doi: 10.4208/jams.121011.011412a Vol. 3, No. 4, pp. 367-374 November 2012 Theoretical comparative study on hydrogen storage of BC 3 and carbon nanotubes Xiu-Ying Liu a,, Li-Ying Zhang
More informationCOMPLEX FLOW OF NANOCONFINED POLYMERS
COMPLEX FLOW OF NANOCONFINED POLYMERS Connie B. Roth, Chris A. Murray and John R. Dutcher Department of Physics University of Guelph Guelph, Ontario, Canada N1G 2W1 OUTLINE instabilities in freely-standing
More informationUnit Cell-Level Thickness Control of Single-Crystalline Zinc Oxide Nanosheets Enabled by Electrical Double Layer Confinement
Unit Cell-Level Thickness Control of Single-Crystalline Zinc Oxide Nanosheets Enabled by Electrical Double Layer Confinement Xin Yin, Yeqi Shi, Yanbing Wei, Yongho Joo, Padma Gopalan, Izabela Szlufarska,
More informationATOMISTIC MODELLING OF CROSSLINKED EPOXY POLYMER
ATOMISTIC MODELLING OF CROSSLINKED EPOXY POLYMER A. Bandyopadhyay 1, P.K. Valavala 2, G.M. Odegard 3 1. Department of Materials Science and Engineering, 512 M&M Building, Michigan Technological University,
More informationEffect of Adsorption in Flow of Gases in Organic Nanopores: A Molecular Dynamics Study. Mohammad Kazemi Ali Takbiri-Borujeni West Virginia University
Effect of Adsorption in Flow of Gases in Organic Nanopores: A Molecular Dynamics Study Mohammad Kazemi Ali Takbiri-Borujeni West Virginia University Multiscale Nature of Gas production Slide 2 Slide 3
More informationCoupling the Level-Set Method with Variational Implicit Solvent Modeling of Molecular Solvation
Coupling the Level-Set Method with Variational Implicit Solvent Modeling of Molecular Solvation Bo Li Math Dept & CTBP, UCSD Li-Tien Cheng (Math, UCSD) Zhongming Wang (Math & Biochem, UCSD) Yang Xie (MAE,
More informationIntroduction. Monday, January 6, 14
Introduction 1 Introduction Why to use a simulation Some examples of questions we can address 2 Molecular Simulations Molecular dynamics: solve equations of motion Monte Carlo: importance sampling Calculate
More informationAdsorption Equilibria. Ali Ahmadpour Chemical Eng. Dept. Ferdowsi University of Mashhad
Adsorption Equilibria Ali Ahmadpour Chemical Eng. Dept. Ferdowsi University of Mashhad Contents Introduction Adsorption isotherm models Langmuir isotherm Volmer isotherm Fowler-Guggenheim isotherm Hill-deBoer
More informationCCSD(T) benchmarks of non-equilibrium water clusters: the importance of monomer deformation
CCSD(T) benchmarks of non-equilibrium water clusters: the importance of monomer deformation Biswajit Santra 1, Angelos Michaelides 1,2, and Matthias Scheffler 1 1 Fritz-Haber-Institut der MPG, Berlin,
More informationLecture 2 Fluid dynamics in microfluidic systems
Lecture 2 Fluid dynamics in microfluidic systems 1) The range of validity of the fluid mechanics equations The hypothesis of the continuum in fluid mechanics (Batchelor, Introduction to Fluids Dynamics)
More informationSupplementary Figure 1. Schematic of rapid thermal annealing process: (a) indicates schematics and SEM cross-section of the initial layer-by-layer
Supplementary Figure 1. Schematic of rapid thermal annealing process: (a) indicates schematics and SEM cross-section of the initial layer-by-layer film configuration, (b) demonstrates schematic and cross-section
More informationModule17: Intermolecular Force between Surfaces and Particles. Lecture 23: Intermolecular Force between Surfaces and Particles
Module17: Intermolecular Force between Surfaces and Particles Lecture 23: Intermolecular Force between Surfaces and Particles 1 We now try to understand the nature of spontaneous instability in a confined
More informationCARBON 2004 Providence, Rhode Island. Adsorption of Flexible n-butane and n-hexane on Graphitized Thermal Carbon Black and in Slit Pores
CARBON Providence, Rhode Island Adsorption of Flexible n-butane and n-hexane on Graphitized Thermal Carbon Black and in Slit Pores D. D. Do* and H. D. Do, University of Queensland, St. Lucia, Qld 7, Australia
More informationarxiv:cond-mat/ v1 [cond-mat.mtrl-sci] 28 Jun 2001
arxiv:cond-mat/665v [cond-mat.mtrl-sci] 28 Jun 2 Matching Conditions in -Continuum Modeling of Materials Weinan E and Zhongyi Huang 2 Department of Mathematics and PACM, Princeton University and School
More informationSupporting information of Self-Assembly, Structure and Pi- Conjugation at the Interface of Poly-3-Hexylthiophene and Carbon Nanotubes
Supporting information of Self-Assembly, Structure and Pi- Conjugation at the Interface of Poly-3-Hexylthiophene and Carbon Nanotubes Details of the molecular dynamics simulations and computational procedures
More informationMolecular modeling and simulation in chemistry
Molecular modeling and simulation in chemistry 1/20 Elements of modeling: Nuclei + electrons + photons: QED Nuclei + electrons: Schrödinger equation Auxiliary interaction centers (sites) Atoms classical
More informationWater models in classical simulations
Water models in classical simulations Maria Fyta Institut für Computerphysik, Universität Stuttgart Stuttgart, Germany Water transparent, odorless, tasteless and ubiquitous really simple: two H atoms attached
More informationMolecular Dynamics Simulation of Fracture of Graphene
Molecular Dynamics Simulation of Fracture of Graphene Dewapriya M. A. N. 1, Rajapakse R. K. N. D. 1,*, Srikantha Phani A. 2 1 School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
More informationLecture 11: Potential Energy Functions
Lecture 11: Potential Energy Functions Dr. Ronald M. Levy ronlevy@temple.edu Originally contributed by Lauren Wickstrom (2011) Microscopic/Macroscopic Connection The connection between microscopic interactions
More informationSurface Forces & Liquid Films (Answers to Exercise Problems)
//5 Surface Forces & Liquid Films (nswers to Exercise Problems) Wuge H. Briscoe wuge.briscoe@bris.ac.uk URL: wugebrisco7.wix.com/briscoegroup Exercise : van der Waals forces & liquid films When octane
More informationEfficient viscosity estimation from molecular dynamics simulation via momentum impulse relaxation
JOURNAL OF CHEMICAL PHYSICS VOLUME 113, NUMBER 6 8 AUGUST 2000 Efficient viscosity estimation from molecular dynamics simulation via momentum impulse relaxation Gaurav Arya, Edward J. Maginn, a) and Hsueh-Chia
More information3rd Advanced in silico Drug Design KFC/ADD Molecular mechanics intro Karel Berka, Ph.D. Martin Lepšík, Ph.D. Pavel Polishchuk, Ph.D.
3rd Advanced in silico Drug Design KFC/ADD Molecular mechanics intro Karel Berka, Ph.D. Martin Lepšík, Ph.D. Pavel Polishchuk, Ph.D. Thierry Langer, Ph.D. Jana Vrbková, Ph.D. UP Olomouc, 23.1.-26.1. 2018
More informationIntensity (a.u.) Intensity (a.u.) Raman Shift (cm -1 ) Oxygen plasma. 6 cm. 9 cm. 1mm. Single-layer graphene sheet. 10mm. 14 cm
Intensity (a.u.) Intensity (a.u.) a Oxygen plasma b 6 cm 1mm 10mm Single-layer graphene sheet 14 cm 9 cm Flipped Si/SiO 2 Patterned chip Plasma-cleaned glass slides c d After 1 sec normal Oxygen plasma
More information, to obtain a way to calculate stress from the energy function U(r).
BIOEN 36 014 LECTURE : MOLECULAR BASIS OF ELASTICITY Estimating Young s Modulus from Bond Energies and Structures First we consider solids, which include mostly nonbiological materials, such as metals,
More informationFRICTION. Friction: FRICARE = to rub (Latin)
FRICTION 1 Friction: FRICARE = to rub (Latin) Resisting force (F) tangential to the interface between two bodies when, under the action of an external force, one body moves or tends to move relative to
More informationRoughness picture of friction in dry nanoscale contacts
Roughness picture of friction in dry nanoscale contacts Yifei Mo 1 and Izabela Szlufarska 1,2 1 Materials Science Program, University of Wisconsin, Madison, Wisconsin 53706-1595, USA 2 Department of Materials
More informationFRICTION FORCE FOR BOUNDARY LUBRICATION
Nanomaterials: Applications and Properties (NAP-11). Vol. 1, Part I 7 FRICTION FORCE FOR BOUNDARY LUBRICATION Iakov A. Lyashenko * Sumy State University, R-Korsakov, 47, Sumy, Ukraine ABSTRACT A thermodynamic
More informationarxiv:cond-mat/ v1 [cond-mat.mtrl-sci] 29 Mar 2006
Impact of molecular structure on the lubricant squeeze-out between curved surfaces with long range elasticity arxiv:cond-mat/0603791v1 [cond-mat.mtrl-sci] 29 Mar 2006 U. Tartaglino, 1,2 I.M. Sivebaek,
More informationNanotube AFM Probe Resolution
Influence of Elastic Deformation on Single-Wall Carbon Nanotube AFM Probe Resolution Ian R. Shapiro, Santiago D. Solares, Maria J. Esplandiu, Lawrence A. Wade, William A. Goddard,* and C. Patrick Collier*
More informationSoot - Developing anisotropic potentials from first principles for PAH molecules. Tim Totton, Alston Misquitta and Markus Kraft 12/11/2009
Soot - Developing anisotropic potentials from first principles for PAH molecules. Tim Totton, Alston Misquitta and 12/11/2009 HRTEM images of soot Some evidence for different soot structures based on different
More informationMolecular Modelling. part of Bioinformatik von RNA- und Proteinstrukturen. Sonja Prohaska. Leipzig, SS Computational EvoDevo University Leipzig
part of Bioinformatik von RNA- und Proteinstrukturen Computational EvoDevo University Leipzig Leipzig, SS 2011 Protein Structure levels or organization Primary structure: sequence of amino acids (from
More informationScanning Force Microscopy II
Scanning Force Microscopy II Measurement modes Magnetic force microscopy Artifacts Lars Johansson 1 SFM - Forces Chemical forces (short range) Van der Waals forces Electrostatic forces (long range) Capillary
More information