scholarly journals Studies of the molecular dynamics in polyurethane networks with hyperbranched crosslinkers of different coordination numbers

2007 ◽  
Vol 105 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Przemyslaw Czech ◽  
Lidia Okrasa ◽  
Jacek Ulanski ◽  
Gisele Boiteux ◽  
Francoise Mechin ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Coordination Numbers ◽  
Polyurethane Networks

Studies of molecular dynamics in polyurethane networks with hyperbranched polyester Boltorn®H30 as a crosslinker

2007 ◽  
Vol 353 (47-51) ◽  
pp. 4293-4297 ◽  
Author(s):  
Lidia Okrasa ◽  
Przemyslaw Czech ◽  
Gisèle Boiteux ◽  
Francoise Méchin ◽  
Jacek Ulanski
Keyword(s):  
Molecular Dynamics ◽  
Hyperbranched Polyester ◽  
Polyurethane Networks

scholarly journals Atomistic Nodal Approach: a General Molecular Dynamics Method For Computing Local Thermal Conductance at Atomistic Resolution

2021 ◽  
Author(s):  
Mingxuan Jiang ◽  
Juan D. Olarte-Plata ◽  
Fernando Bresme
Keyword(s):  
Molecular Dynamics ◽  
Thermal Transport ◽  
Temperature Drop ◽  
Thermal Conductance ◽  
Fundamental Property ◽  
Lower Surface ◽  
Coordination Numbers ◽  
Interfacial Thermal Conductance ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations

The Interfacial Thermal Conductance (ITC) is a fundamental property of mate- rials and has particular relevance at the nanoscale. The ITC quanti�es the thermal resistance between materials of dierent compositions or between uids in contact with materials. Furthermore, the ITC determines the rate of cooling/heating of the materi- als and the temperature drop across the interface. Here we propose a method to com- pute local ITCs and temperature drops of nanoparticle- uid interfaces. Our approach resolves the ITC at the atomic level using the atomic coordinates of the nanomaterial as nodes to compute local thermal transport properties. We obtain high-resolution descriptions of the interfacial thermal transport by combining the atomistic nodal ap- proach, computational geometry techniques and \computational farming" using Non- Equilibrium Molecular Dynamics simulations. We illustrate our method by analyzing various nanoparticles as a function of their size and geometry, targeting experimentally relevant structures like capped octagonal rods, cuboctahedrons, decahedrons, rhombic dodecahedrons, cubes, icosahedrons, truncated octahedrons, octahedrons and spheres. We show that the ITC of these very dierent geometries can be accurately described in terms of the local coordination number of the atoms in the nanoparticle surface. Nanoparticle geometries with lower surface coordination numbers feature higher ITCs, and the ITC generally increases with decreasing particle size.

Ion Hydration Under Pressure: A Molecular Dynamics Study

2013 ◽  
Vol 68 (1-2) ◽  
pp. 112-122 ◽  
Author(s):  
Maksym Druchok ◽  
Myroslav Holovko
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solutions ◽  
Dynamic Properties ◽  
Ion Hydration ◽  
Coordination Numbers ◽  
Self Diffusion ◽  
Velocity Autocorrelation ◽  
Hydration Behaviour ◽  
Hydration Shells ◽  
Dynamics Simulations

This study is intended to elucidate the role of pressure on the hydration behaviour of ions in aqueous solutions. Molecular dynamics simulations were performed for systems modelling CsF, CsCl, CsBr, and CsI aqueous solutions under ‘normal’ (105 Pa, 298 K) and ‘high pressure’ (4 ·109 Pa, 500 K) conditions. Structural details are discussed in terms of radial distributions functions, coordination numbers, and instantaneous configurations of the ionic hydration shells. The dynamic properties studied include the velocity autocorrelation functions and self-diffusion coefficients of the ions for both pressure regimes. The results indicate strong changes in the hydration behaviour and mobility of the ions.

Hydrophilic dangling chain interfacial segregation in polyurethane networks at aqueous interfaces and its underlying mechanisms: molecular dynamics simulations

2020 ◽  
Vol 22 (45) ◽  
pp. 26351-26363
Author(s):  
Hassan Ghermezcheshme ◽  
Hesam Makki ◽  
Mohsen Mohseni ◽  
Morteza Ebrahimi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Polymer Networks ◽  
Aqueous Interfaces ◽  
Polyurethane Networks ◽  
Interfacial Segregation ◽  
Underlying Mechanisms ◽  
Dynamics Simulations

Brush formation of polymer networks with hydrophilic dangling chains and its underlying mechanisms.

Structural and Dynamical Correlations in Stishovite and High Density Silica Glass

1992 ◽  
Vol 293 ◽  
Author(s):  
Wei Jin ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Density Of States ◽  
Silica Glass ◽  
Bond Angle ◽  
Diffraction Peak ◽  
Static Structure Factor ◽  
Static Structure ◽  
Coordination Numbers ◽  
Intermediate Range Order ◽  
Vibrational Density

AbstractPressure-induced structural transformation from tetrahedral to octahedral coordination and the destruction of intermediate-range order (IRO) are studied in silica glass (a-SiO 2) using the molecular-dynamics (MD) method. Changes in the position and height of the first sharp diffraction peak (FSDP) in the static structure factor, bond lengths, coordination numbers, bond-angle distributions, and statistics of rings are investigated as a function of density. Modifications of the vibrational density of states and participation ratio are also discussed.

STRUCTURE AND DYNAMICAL PROPERTIES OF AuN, N = 12–14 CLUSTERS: MOLECULAR DYNAMICS SIMULATION

2005 ◽  
Vol 16 (01) ◽  
pp. 99-116 ◽  
Author(s):  
ERDEM K. YILDIRIM ◽  
MURAT ATİŞ ◽  
ZİYA B. GÜVENÇ
Keyword(s):  
Molecular Dynamics ◽  
Thermal Quenching ◽  
Melting Behavior ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Coordination Numbers ◽  
Embedded Atom ◽  
Long Time ◽  
Time Average ◽  
Short Time

Using molecular dynamics and thermal quenching methods on the basis of Voter–Chen version of the embedded-atom method, we have studied the melting behavior of Au N (N = 12, 13, 14) clusters. This behavior is described in terms of overall and atom resolved root-mean-square bond-length fluctuations, specific-heat, short- and long-time average coordination numbers of each atom and short-time average temperatures of the clusters. The isomer sampling probabilities are obtained from the thermal quenching of the molten clusters, and their energy-spectrum widths are investigated. Phase change of a cluster takes place with the collective and simultaneous motion of all the atoms.

scholarly journals Atomistic Nodal Approach: a General Molecular Dynamics Method For Computing Local Thermal Conductance at Atomistic Resolution

2021 ◽  
Author(s):  
Mingxuan Jiang ◽  
Juan D. Olarte-Plata ◽  
Fernando Bresme
Keyword(s):  
Molecular Dynamics ◽  
Thermal Transport ◽  
Temperature Drop ◽  
Thermal Conductance ◽  
Fundamental Property ◽  
Lower Surface ◽  
Fluid Interfaces ◽  
Coordination Numbers ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations

The Interfacial Thermal Conductance (ITC) is a fundamental property of materials and has particular relevance at the nanoscale. The ITC quantifies the thermal resistance between materials of different compositions or between fluids in contact with materials. Furthermore, the ITC determines the rate of cooling/heating of the materials and the temperature drop across the interface. Here we propose a method to compute local ITCs and temperature drops of nanoparticle-fluid interfaces. Our approach resolves the ITC at the atomic level using the atomic coordinates of the nanomaterial as nodes to compute local thermal transport properties. We obtain high-resolution descriptions of the interfacial thermal transport by combining the atomistic nodal approach, computational geometry techniques and "computational farming'' using Non-Equilibrium Molecular Dynamics simulations. We illustrate our method by analyzing various nanoparticles as a function of their size and geometry, targeting experimentally relevant structures like capped octagonal rods, cuboctahedrons, decahedrons, rhombic dodecahedrons, cubes, icosahedrons, truncated octahedrons, octahedrons and spheres. We show that the ITC of these very different geometries can be accurately described in terms of the local coordination number of the atoms in the nanoparticle surface. Nanoparticle geometries with lower surface coordination numbers feature higher ITCs, and the ITC generally increases with decreasing particle size.

Structure and Ion Transport Pathways in 0.45Li2O-(0.55-x)P2O5-xB2O3 Glasses

2010 ◽  
Vol 1266 ◽  
Author(s):  
Tho Duc Thieu ◽  
R. Prasada Rao ◽  
Stefan Adams
Keyword(s):  
Molecular Dynamics ◽  
Ion Transport ◽  
Photoelectron Spectroscopy ◽  
Md Simulations ◽  
Structural Effects ◽  
Transport Pathways ◽  
Xps Spectra ◽  
X Ray ◽  
Coordination Numbers ◽  
Bond Valence Analysis

AbstractLithium borophosphate glasses 0.45Li2O-(0.55-x)P2O5-xB2O3 (where 0 ≤ x ≤ 0.40) were investigated focusing on the influence of cation mobility changes due to mixed glass former effect. It was found that glass transition temperature (Tg) increases and molar volume decreases with B2O3 addition. X-ray photoelectron spectroscopy (XPS) spectra showed that besides P-O-P, B-O-B and P=O, P-O-, B-O- bond peaks, an intermediate O1s peak due to P-O-B bonds emerges in glasses with B2O3 contents x ≥ 0.15. Molecular dynamics (MD) simulations for the same systems have been performed with an optimized potential, fitted to match bond lengths, coordination numbers and ionic conductivity (σdc). Structural effects on ion transport as the origin of the mixed glass former effect can be quantified by applying the bond valence analysis (BV) approach to the equilibrated MD trajectories.

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