Molecular dynamics simulation of shish-kebab crystallization of polyethylene: Unraveling the effects of molecular weight distribution

2019 ◽  
Vol 150 (18) ◽  
pp. 184114 ◽  
Author(s):  
Li Zhao ◽  
Yanling Hu ◽  
Yunqi Shao ◽  
Zhen Liu ◽  
Boping Liu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Dynamics Simulation

Effect of Molecular Weight on Lubricant Depletion in a Heat Assisted Magnetic Recording System

2017 ◽  
Author(s):  
Deng Pan ◽  
Wenping Song
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Magnetic Recording ◽  
Recording System ◽  
Dynamics Simulation ◽  
Disk System ◽  
Heat Assisted Magnetic Recording ◽  
Lubricant Depletion

A model for studying lubricant depletion in HAMR slider/disk system was developed based on molecular dynamics simulation. We found that the lubricant molecular weight has small effect on lubricant depletion.

scholarly journals A double-edged sword: supramolecular complexes of triazavirine display multicenter binding effects which influence aggregate formation

2018 ◽  
Author(s):  
Yana A Zabrodskaya ◽  
Alexey V Shvetsov ◽  
Vladimir B Tsvetkov ◽  
Vladimir V Egorov
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Antiviral Activity ◽  
Small Molecule ◽  
Broad Spectrum ◽  
Dynamics Simulation ◽  
Supramolecular Complexes ◽  
Aggregate Formation

Triazavirine (TZV), a small molecule with a broad spectrum of antiviral activity, shows a tendency to induce the aggregation of melittin (MLT), a cationic membrane-disrupting peptide from the poison of the European bee. In MLT:TZV mixtures, high molecular weight precipitates form once a critical MLT:TZV ratio has been exceeded. Molecular dynamics simulation of MLT-TZV interactions, followed by molecular docking, led us to the hypothesis of multicenter binding of TZV supramolecular complexes to MLT.

scholarly journals Evaluation of Radiation Resistance of Polystyrene Using Molecular Dynamics Simulation

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 346
Author(s):  
Yeong-Heum Yeon ◽  
Ha-Eun Shim ◽  
Jin-Hyung Park ◽  
Nam-Ho Lee ◽  
Jae-Yeon Park ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Average Molecular Weight ◽  
Absorbed Dose ◽  
Gel Permeation Chromatography ◽  
Dynamics Simulation ◽  
Molecular Weight Distributions ◽  
Radiation Enhancement ◽  
Γ Rays

The scission rates of polystyrene and fluorinated polystyrene irradiated in an irradiation facility with Co-60 γ-rays were determined using molecular dynamics simulation and gel permeation chromatography (GPC) molecular weight distributions. The prediction was based on the assumption that γ-ray energy is transferred to the initial velocity of the primary knock-on atom. We employed a molecular dynamics simulation procedure to compute the changes in bond length between the connections for selected values of the absorbed dose and compared the calculated values with measurements made on the irradiated samples. The samples were exposed to four different absorbed doses of 25, 50, 75, and 100 kGy. The scission process and scission ratio were simulated with LAMMPS with ReaxFF potential for each bond, and we compared the simulation results with the experimental data especially measuring average molecular weight to evaluate the effect of fluorination on radiation enhancement.

scholarly journals Synthesis and Molecular Dynamics Simulation of Amphiphilic Low Molecular Weight Polymer Viscosity Reducer for Heavy Oil Cold Recovery

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6856
Author(s):  
Chao Ma ◽  
Xingyu Liu ◽  
Longlong Xie ◽  
Yan Chen ◽  
Wendong Ren ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Potential Energy ◽  
Network Structure ◽  
Heavy Oil ◽  
Dynamics Simulation ◽  
Viscosity Reduction ◽  
Low Molecular Weight ◽  
Viscosity Reducer

In order to reduce the viscosity of heavy oil, the performance of emulsifying viscosity reducers is limited. In this study, a new kind of amphiphilic low molecular weight viscosity reducer was prepared by emulsion copolymerization of acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and Butene benzene (PB). The synthesis feasibility and viscosity reduction mechanism of viscosity reducer in heavy oil were explored using Materials Studio software from the perspective of molecular dynamics. The results of the molecular dynamics simulation revealed that the addition of viscosity reducer into heavy oil varied the potential energy, non-potential energy, density and hydrogen bond distribution of heavy oil. Benefiting from its structure, the benzene ring in PB was well embedded in the interlayer structure of asphaltene, contributing to weaken the network structure of the heavy oil. Moreover, the two strong polar groups (COO− and SO3−) of AA and AMPS, which constituted the branched chains of the viscosity reducer’s molecular structure, gradually disassembled the network structure from the ‘inward’ to the ‘outward’ of the heavy oil network structure, thereby driving heavy oil viscosity reduction (as clarified by molecular dynamics). Owing to its temperature resistance, this kind of new amphiphilic low molecular copolymer could be an effective viscosity reducer for heavy oil cold recovery at elevated temperatures.

scholarly journals Lysine Dendrigraft Nanocontainers. Influence of Topology on Their Size and Internal Structure

Pharmaceutics ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 129 ◽  
Author(s):  
Boris Okrugin ◽  
Maxim Ilyash ◽  
Denis Markelov ◽  
Igor Neelov
Keyword(s):  
Drug Delivery ◽  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Density Profile ◽  
Simulation Study ◽  
Biomedical Applications ◽  
Dynamics Simulation ◽  
Third Generation ◽  
Internal Structures

Poly-l-ysine dendrigrafts are promising systems for biomedical applications due to their biodegradability, biocompatibility, and similarity to dendrimers. There are many papers about the use of dendrigrafts as nanocontainers for drug delivery. At the same time, the number of studies about their physical properties is limited, and computer simulations of dendrigrafts are almost absent. This paper presents the results of a systematic molecular dynamics simulation study of third-generation lysine dendrigrafts with different topologies. The size and internal structures of the dendrigrafts were calculated. We discovered that the size of dendrigrafts of the same molecular weight depends on their topology. The shape of all studied dendrigrafts is close to spherical. Density profile of dendrigrafts depends on their topology.

scholarly journals Diffusion and Friction Dynamics of Probe Molecules in Liquid n-Alkane Systems: A Molecular Dynamics Simulation Study

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Song Hi Lee
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Power Law ◽  
Simulation Study ◽  
Dynamics Simulation ◽  
Probe Molecules ◽  
Self Diffusion ◽  
The Matrix ◽  
Friction Dynamics

We present a molecular dynamics simulation study of the probe diffusion and friction dynamics of Lennard-Jones particles in a series of liquid n-alkane systems from C12 up to C400 at 318 K, 418 K, 518 K, and 618 K, to investigate the power law dependence of self-diffusion of polymer liquids on their molecular weights. Two LJ particles MY1 with a mass of 114 g/mol and MY2 with a mass of 225 g/mol are used as probes to model methyl yellow. We observed that a clear transition in the power law dependence of n-alkane self-diffusion on the molecular weight (M) of n-alkane, Dself∼M−γ, occurs in the range C120∼C160 at temperatures of 318 K, 418 K, and 518 K, corresponding to a crossover from the “oligomer” to the “Rouse” regime. We also observed that a clear transition in the power law dependence of the diffusion coefficient DMY2 on the molecular weight (M) of n-alkane, DMY2∼M−γ, occurs at low temperatures. The exponent γ for DMY2 shows a sharp transition from 1.21 to 0.52 near C36 at 418 K and from 1.54 to 0.60 near C36 at 318 K. However, no such transition is found for the probe molecule MY2 at temperatures of 518 K and 618 K and for MY1 probe at temperatures of 418 K, 518 K, and 618 K, but the power law exponent γ for MY1 at 318 K shows instead a linear or a rather slow transition. The dependence of the probe diffusion (DMY2) on the matrix molecular weight (M) reflects a significant change of the matrix dynamics associated with the probe diffusion: a crossover from the “solvent-like” to the “oligomer” regime. As the molecular weight of n-alkane increases, the ratio of Dself/DMY2 becomes less than 1 and the probe molecules encounter, in turn, two different microscopic frictions depending on MMY/Mmatrix and the temperature. It is believed that a reduction in the microscopic friction on the probe molecules that diffuse at a rate faster than the solvent fluctuations leads to large deviations of slope from the linear dependence of the friction of MY2 on the chain length of the n-alkane at 318 K and 418 K.

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