scholarly journals Molecular Dynamics Simulation of Polyacrylamide Adsorption on Cellulose Nanocrystals

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1256 ◽  
Author(s):  
Darya Gurina ◽  
Oleg Surov ◽  
Marina Voronova ◽  
Anatoly Zakharov
Keyword(s):  
Molecular Dynamics ◽  
Cellulose Nanocrystals ◽  
Water Environment ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Radial Distribution Functions ◽  
Dynamical Characteristics ◽  
Polymer Interactions ◽  
Dynamics Simulations

Classical molecular dynamics simulations of polyacrylamide (PAM) adsorption on cellulose nanocrystals (CNC) in a vacuum and a water environment are carried out to interpret the mechanism of the polymer interactions with CNC. The structural behavior of PAM is studied in terms of the radius of gyration, atom–atom radial distribution functions, and number of hydrogen bonds. The structural and dynamical characteristics of the polymer adsorption are investigated. It is established that in water the polymer macromolecules are mainly adsorbed in the form of a coil onto the CNC facets. It is found out that water and PAM sorption on CNC is a competitive process, and water weakens the interaction between the polymer and CNC.

scholarly journals Water Effects on Molecular Adsorption of Poly(N-vinyl-2-pyrrolidone) on Cellulose Nanocrystals Surfaces: Molecular Dynamics Simulations

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2155 ◽  
Author(s):  
Darya Gurina ◽  
Oleg Surov ◽  
Marina Voronova ◽  
Anatoly Zakharov ◽  
Mikhail Kiselev
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonds ◽  
Cellulose Nanocrystals ◽  
Monomer Unit ◽  
Water Environment ◽  
Hydrophobic Surface ◽  
Distribution Functions ◽  
Radius Of Gyration ◽  
Dynamics Simulations ◽  
Globular Form

Models of interaction between a poly(N-vinyl-2-pyrrolidone) macromolecule and a fragment of Iβ-cellulose were built in a vacuum and water environment. The models were made to interpret the mechanism of interaction of the polymer and cellulose nanocrystals by the classical molecular dynamics method. The structural behavior of a poly(N-vinyl-2-pyrrolidone) macromolecule in water has been studied in terms of the radius of gyration, atom–atom radial distribution functions and number of hydrogen bonds. It was found that the polymer has a high affinity with the solvent and each monomer unit has on average 0.5 hydrogen bonds. The structural and energy characteristics of the polymer adsorption were investigated at different initial positions of the poly(N-vinyl-2-pyrrolidone) macromolecule relative to the cellulose fragment. It was observed that the polymer macromolecule was mainly adsorbed on the cellulose fragment in the globular form. Moreover, in the solvent the interaction of poly(N-vinyl-2-pyrrolidone) with the cellulose hydrophobic surface was stronger than that with the hydrophilic one. This study will show that the presence of water makes the interaction between the polymer and cellulose weaker than in a vacuum, and the polymer and cellulose mainly interact through their solvation shells.

Molecular Dynamics Study of the Structural and Dynamical Properties of Liquid Tetrahydrofuran

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1342-1344 ◽  
Author(s):  
W. Drabowicz
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Radial Distribution ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Radial Distribution Functions ◽  
Frequency Spectra ◽  
Autocorrelation Functions ◽  
Dynamical Properties

AbstractA molecular dynamics simulation has been performed to investigate the structural and dynamical properties of liquid tetrahydrofuran. In particular, we have calculated six radial distribution functions, translational and rotational autocorrelation functions and their associated frequency spectra.

Molecular Dynamics Studies of Nanoparticles of Energetic Materials

2003 ◽  
Vol 800 ◽  
Author(s):  
Saman Alavi ◽  
Gustavo F. Velardez ◽  
Donald L. Thompson
Keyword(s):  
Molecular Dynamics ◽  
Correlation Function ◽  
Solid State ◽  
Molecular Dynamics Simulations ◽  
Energetic Materials ◽  
Center Of Mass ◽  
Distribution Functions ◽  
Radial Distribution Functions ◽  
Dynamics Simulations ◽  
Dipole Correlation

ABSTRACTThe structural properties of several nanoparticles of 2,4,6,8,10,12-hexanitrohexaazaiso-wurtzitane, HNIW or CL-20, are studied by using molecular dynamics simulations. The internal structure of the CL-20 molecule is held rigid and the intermolecular interactions in the nanoparticles are taken from a previously developed force field. [Sorescu et al., J. Phys. Chem. B, 102, 948 (1998)] Molecular dynamics simulations of solid-like and annealed nanoparticles with 48 and 88 CL-20 molecules have been carried out in the solid-state range of temperatures from 50 to 500 K. The center-of-mass to center-of-mass radial distribution functions, dipole-dipole correlation function, the orientations of the surface dipoles, and the density of the nanoparticles were calculated at fixed temperatures for the nanoparticles.

scholarly journals Molecular dynamics simulation of an aqueous Na2SO4 solution

2018 ◽  
Vol 72 (2) ◽  
pp. 67 ◽  
Author(s):  
Krzysztof Nieszporek ◽  
Jolanta Nieszporek
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bond ◽  
Molecular Dynamics Simulation ◽  
Sodium Sulfate ◽  
Water Solution ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Geometrical Parameters ◽  
Radial Distribution Functions ◽  
Hydration Shells

<p>The structure of sodium sulfate in tip3p water solution with the concentration of 0.1191 mol/dm<sup>3</sup> was studied by means of classical molecular dynamics. Both ions have clear hydration shells. The comparison between radial distribution functions and cumulative numbers of selected atoms around the reference one makes it possible to precisely describe the structure of investigated system. Applying such tools geometrical parameters of the hydrogen bond of the dimer SO<sub>4</sub><sup>2-</sup>/H<sub>2</sub>O have been obtained.</p><p> </p>

scholarly journals Structural and Dynamic Properties of Hydrophobic Eutectic Solvents Based on Menthol and Fatty Acids: a Molecular Dynamics Simulation Study

2021 ◽  
Author(s):  
Samaneh Barani Pour ◽  
Jaber Jahanbin Sardroodi ◽  
Alireza Rastkar Ebrahimzadeh
Keyword(s):  
Molecular Dynamics ◽  
Fatty Acids ◽  
Dynamic Properties ◽  
Mean Square Displacement ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Eutectic Mixtures ◽  
Dynamical Properties ◽  
Reorientation Dynamics ◽  
Dynamics Simulations

Abstract The structural and dynamical properties of the binary mixture of Menthol (MEN) and Fatty acids (FAs) were investigated using molecular dynamics simulations. We focused on the relationship between the structural and dynamical properties of the eutectic mixtures of MEN and FAs with different molar percentages of FAs. Structural properties of the eutectic mixtures were characterized by calculating the combined distribution functions(CDFs), the radial distribution functions (RDFs), and the angular distribution functions (ADFs), and the Hydrogen bonding network between species and Spatial distribution functions (SDF). Further interaction between menthol and Caprylic acid molecules was confirmed by the results of these analyzes. Also, the transport properties of the mixtures were investigated by using the mean square displacement (MSD) of the centers of mass of the species, self-diffusion coefficients and vector reorientation dynamics (VRD) of bonds. The simulation results indicated that intermolecular interactions have a significant effect on the dynamic properties of species.

Study of dispersion of boron nitride nanotubes by triton X-100 surfactant using molecular dynamics simulations

2014 ◽  
Vol 13 (07) ◽  
pp. 1450063 ◽  
Author(s):  
S. Mahmood Fatemi ◽  
Masumeh Foroutan
Keyword(s):  
Boron Nitride ◽  
Surfactant Solution ◽  
Boron Nitride Nanotubes ◽  
Distribution Functions ◽  
Radius Of Gyration ◽  
Water Molecules ◽  
Radial Distribution Functions ◽  
Interfacial Angle ◽  
Dynamics Simulations ◽  
Triton X

In this study, the dispersion of aggregated boron nitride nanotubes (BNNTs) in aqueous triton X-100 surfactant solution is studied using molecular dynamic simulation. The results indicate that how in the presence of the surfactant, a space between two BNNTs is created, which leads to the dispersion of the BNNTs. The radial distribution functions (RDFs) of the atoms of BNNTs and hydrophilic and hydrophobic segments of the surfactant respect to atoms of water molecules show that in the presence of the surfactant, a layer of water molecules is located in the neighborhood of the BNNTs and then hydrophobic and hydrophilic segments of the surfactant reside at more distances of the BNNTs. In the absence of the surfactant, the hydrogen bond between nitrogen atom of the BNNT and hydrogen atom of water molecules is established and the distance between water molecules and the BNNTs is decreased with increase of the surfactant concentration. The obtained results for the surfactant radius of gyration and the interfacial angle between two BNNTs reveal more information about the arrangement of the surfactants around the BNNTs in the presence and in the absence of water molecules.

scholarly journals Dynamic and Static Properties of Aqueous NaCl Solutions at 25°C as a Function of NaCl Concentration: A Molecular Dynamics Simulation Study

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Song Hi Lee
Keyword(s):  
Molecular Dynamics ◽  
Radial Distribution ◽  
Dynamic Properties ◽  
Md Simulations ◽  
Distribution Functions ◽  
Molar Conductivity ◽  
Dynamics Simulation ◽  
Radial Distribution Functions ◽  
Deep Minimum ◽  
Nacl Concentration

We present the result of molecular dynamics (MD) simulations to calculate the molar conductivity Λ m =   λ N a + +   λ C l − of NaCl in SPC/E water at 25°C as a function of NaCl concentration (c) using Ewald sums employing a velocity Verlet algorithm. It is found that the MD result for Λm with Ewald sum parameter κ = 0.10 Å−1 gives the closest one to the experimental data and that the obtained radial distribution functions g i i (r) with κ = 0.10 Å−1 show a dramatic change with a very deep minimum of g NaCl (r) and, as a result, sharp maxima of g NaNa (r) and g ClCl (r) at the distance 9.95 Å, which indicates a characteristic of ionic atmosphere, the basis of the Debye–Hückel theory of ionic solutions. The static and dynamic properties of NaCl (aq) solutions are analyzed in terms of radial distribution functions, hydration numbers, coordination numbers around Na+ and Cl−, residence times of water around Na+ and Cl−, water diffusion, and ion-ion electrostatic energies to explain the behavior of the molar conductivity Λm of NaCl obtained from our MD simulations.

scholarly journals The Thermal Agitated Phase Transitions on the Ti32 Nanocluster: a Molecular Dynamics Simulation Study

2021 ◽  
Vol 74 ◽  
Author(s):  
Tshegofatso M. Phaahla ◽  
Alexey A. Sokol ◽  
Charles R.A. Catlow ◽  
Scott M. Woodley ◽  
Phuti E. Ngoepe ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Phase Transitions ◽  
Molecular Dynamics Simulation ◽  
Melting Point ◽  
Radial Distribution ◽  
Simulation Software ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Radial Distribution Functions

ABSTRACT Molecular dynamics simulations were performed to investigate the stability with respect to increasing the simulated temperature from 300 to 2400 K of an isolated cluster composed of 32 titanium atoms. The interatomic interactions were modelled using Gupta potentials as implemented within the classical molecular dynamics simulation software DL_POLY. The radial distribution functions (RDF), diffusion coefficient, and density profiles were examined to study the structural changes as a function of temperature. It was found that the Ti32 nanocluster exhibits temperature structural transition. The icosahedron and pentagonal bi-pyramid structures were found to be the most dominant building block fragments. Deformation of the nanocluster was also measured by diffusion coefficient, and it was found that the Ti32 are mobile above the bulk melting point. The phase transitions from solid to liquid have been identified by a simple jump in the total energy curve, with the predicted melting temperature near the bulk melting point (1941.15 K). As expected, the RDF's and density profile peaks decrease with increasing temperature. Keywords: Molecular dynamics, titanium cluster, radial distribution functions, diffusion coefficient, mean square displacement.

scholarly journals Structure Analysis of Amorphous and Liquid Magnesium Silicate

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Mai Thi Lan ◽  
Nguyen Thi Thao
Keyword(s):  
Molecular Dynamics ◽  
Boundary Condition ◽  
Distribution Function ◽  
Molecular Dynamics Simulation ◽  
Radial Distribution ◽  
Magnesium Silicate ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Radial Distribution Functions ◽  
The One

We use the Oganov potentials and period boundary condition to perform molecular dynamics simulation of amorphous and liquid Mg2SiO4 systems under pressures 0 GPa and 40 GPa. We clarify structure of amorphous Mg2SiO4 at 0 and 40 GPa and compared with the one of Mg2SiO4 at liquid state. Especially, the origin of sub-peaks in radial distribution function of O-O, Si-Si and Mg-Mg pairs is explained clearly. The change of radial distribution functions, coordination number and the number of all types of bonds including the corner-, edge- and face-sharing bonds is also discussed in detail in this paper.

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