scholarly journals Molecular Dynamics Simulation on the Effect of Bonding Pressure on Thermal Bonding of Polymer Microfluidic Chip

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 557 ◽  
Author(s):  
Mingyong Zhou ◽  
Xiang Xiong ◽  
Dietmar Drummer ◽  
Bingyan Jiang
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Md Simulations ◽  
Equivalent Strain ◽  
Bonding Process ◽  
Tensile Failure ◽  
Dynamics Simulation ◽  
Thermal Bonding ◽  
Yield Strain ◽  
Bonding Pressure

Thermal bonding technology is the most commonly used approach in bonding injection-molded microfluidic chips. Although the bonding mechanism is still under debate, the molecular dynamics (MD) method can provide insight into the bonding process on a macromolecular level. In this study, MD simulations for thermal bonding of PMMA substrate and cover sheet were performed. The molecule configuration and density distribution during the thermal bonding process were studied. The effects of bonding pressure on the equivalent strain, joining energy and diffusion coefficient were investigated. The debonding process was simulated to analyze the bonding strength and failure mechanism. Simulation results show that penetration mainly takes place near the interface area. Although the final density increases slightly with increasing pressure, the bonding interface is still insufficiently filled. The equivalent strain grows faster than that in the later stage because of the gap at the interface. The bonding pressure shows clear effects on the joining energy, diffusion coefficient and stress–strain behavior. Tensile failure occurs at the interface, with PMMA chains stretched between two layers. The majority of the change in potential energy is correlated with the change in non-bonded energy. At yield strain, the low-density defect at the interface weakens the tensile strength of bonded chip.

scholarly journals Understanding Covalent Grafting of Nanotubes onto Polymer Nanocomposites: Molecular Dynamics Simulation Study

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2621
Author(s):  
Seunghwa Yang
Keyword(s):  
Molecular Dynamics ◽  
Load Transfer ◽  
Cell Model ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Covalent Grafting ◽  
Modelling Strategies ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
External Loads

Here, we systematically interrogate the effects of grafting single-walled (SWNT) and multi-walled carbon nanotubes (MWNT) to polymer matrices by using molecular dynamics (MD) simulations. We specifically investigate key material properties that include interfacial load transfer, alteration of nanotube properties, and dispersion of nanotubes in the polymer matrix. Simulations are conducted on a periodic unit cell model of the nanocomposite with a straight carbon nanotube and an amorphous polyethylene terephthalate (PET) matrix. For each type of nanotube, either 0%, 1.55%, or 3.1% of the carbon atoms in the outermost nanotubes are covalently grafted onto the carbon atoms of the PET matrix. Stress-strain curves and the elastic moduli of nanotubes and nanocomposites are determined based on the density of covalent grafting. Covalent grafting promotes two rivalling effects with respect to altering nanotube properties, and improvements in interfacial load transfer in the nanocomposites are clearly observed. The enhanced interface enables external loads applied to the nanocomposites to be efficiently transferred to the grafted nanotubes. Covalent functionalization of the nanotube surface with PET molecules can alter the solubility of nanotubes and improve dispersibility. Finally, we discuss the current limitations and challenges in using molecular modelling strategies to accurately predict properties on the nanotube and polymers systems studied here.

A Study on the Uniaxial Tension of FCC Metals at Nano Level Using MD

2008 ◽  
Vol 32 ◽  
pp. 255-258
Author(s):  
Bohayra Mortazavi ◽  
Akbar Afaghi Khatibi
Keyword(s):  
Molecular Dynamics ◽  
Uniaxial Tension ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Face Centered Cubic ◽  
Engineering Strain ◽  
Fcc Metals ◽  
Engineering Stress ◽  
Nano Science ◽  
Face Centered

Molecular Dynamics (MD) are now having orthodox means for simulation of matter in nano-scale. It can be regarded as an accurate alternative for experimental work in nano-science. In this paper, Molecular Dynamics simulation of uniaxial tension of some face centered cubic (FCC) metals (namely Au, Ag, Cu and Ni) at nano-level have been carried out. Sutton-Chen potential functions and velocity Verlet formulation of Noise-Hoover dynamic as well as periodic boundary conditions were applied. MD simulations at different loading rates and temperatures were conducted, and it was concluded that by increasing the temperature, maximum engineering stress decreases while engineering strain at failure is increasing. On the other hand, by increasing the loading rate both maximum engineering stress and strain at failure are increasing.

Molecular Dynamics Simulation of a Pullout Test on a Carbon Nanotube in a Polymer Matrix

2014 ◽  
Vol 1700 ◽  
pp. 61-66
Author(s):  
Guttormur Arnar Ingvason ◽  
Virginie Rollin
Keyword(s):  
Molecular Dynamics ◽  
Polymer Matrix ◽  
Large Scale ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Atomistic Simulations ◽  
Polymer Molecules ◽  
Molecular Potential ◽  
Pull Out ◽  
Walled Carbon Nanotubes

ABSTRACTAdding single walled carbon nanotubes (SWCNT) to a polymer matrix can improve the delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics (MD) simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential. This potential includes non-bonded interactions, as well as bonds, angles and dihedrals to create a MD model for a SWCNT and EPON 862/DETDA (Diethyltoluenediamine) polymer matrix. Two simulations were performed in order to test the implementation of the COMPASS parameters. The first one was a tensile test on a SWCNT, leading to a Young’s modulus of 1.4 TPa at 300K. The second one was a pull-out test of a SWCNT from an originally uncured EPON 862/DETDA matrix.

Momentum Removal to Obtain the Position-Dependent Diffusion Constant in Constrained Molecular Dynamics Simulation

2021 ◽  
Author(s):  
Kazushi Fujimoto ◽  
Tetsuro Nagai ◽  
Tsuyoshi Yamaguchi
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Mass Velocity ◽  
Center Of Mass ◽  
Heterogeneous Systems ◽  
Diffusion Constant ◽  
Dynamics Simulation ◽  
Coulombic Interaction ◽  
Ewald Method ◽  
Theoretical Predictions

<div>The position-dependent diffusion coefficient along with free energy profile are important parameters needed to study mass transport in heterogeneous systems such as biological and polymer membranes, and molecular dynamics (MD) calculation is a popular tool to obtain them. Among many methodologies, the Marrink-Berendsen (MB) method is often employed to calculate the position-dependent diffusion coefficient, in which the autocorrelation function of the force on a fixed molecule is related to the friction on the molecule. However, the diffusion coefficient is shown to be affected by the period of the removal of the center-of-mass velocity, which is necessary when performing MD calculations using the Ewald method for Coulombic interaction. We have clarified theoretically in this study how this operation affects the diffusion coefficient calculated by the MB method, and the theoretical predictions are proven by MD calculations. Therefore, we succeeded in providing guidance on how to select an appropriate the period of the removal of the center-of-mass velocity in estimating the position-dependent diffusion coefficient by the MB method. This guideline is applicable also to the Woolf-Roux method.</div>

Molecular Dynamics Simulation Study of the Effect of Ni, Fe, Cu on Cryolite Molten Salt System 78% Na3AlF6-9.5%AlF3-5.0%CaF2-7.5%-Al2O3

2021 ◽  
Vol 1026 ◽  
pp. 39-48
Author(s):  
Han Bing He ◽  
Yu Si Wang ◽  
Ze Xiang Luo ◽  
Jing Zeng
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Molten Salt ◽  
Diffusion Mechanism ◽  
Research Work ◽  
Dynamics Simulation ◽  
Salt System ◽  
Electrolyte System ◽  
Aluminum Composite ◽  
Molten Salt System

The effect of different additives Ni, Fe, Cu on the structure and properties of electrolyte system 78% Na3AlF6- -9.5%AlF3-5.0%CaF2-7.5%Al2O3 at 1200K and 1.01Mpa was studied by molecular dynamics method. The radial distribution function, coordination number, diffusion coefficient, conductivity, and viscosity of the system were discussed in detail. The results demonstrated that the order of the self-diffusion coefficient of ions in the electrolyte system is: Na+ > F- > O2- > Ca2+ >Al3+. The addition of Ni and Fe connected the free aluminum composite ion groups in the system through fluorine bridges, which enhanced the interaction between Al3+ and Al3+. The addition of Cu weakened the interaction between Al3 + and Al3+ and the F-. The interaction between Al3+ and Na+, [AlF7]4- ionic groups might appeared in the melt system. After adding NiO, Fe2O3, and Cu, the electrical conductivity of the system increased, and the viscosity decreased. The research work revealed the influence of Ni, Fe, Cu on the ion existence form, mobility, inter-ion interaction and diffusion mechanism of cryolite molten salt system, which has important guiding significance for aluminum electrolysis production.

scholarly journals An Analysis Based on Molecular Docking and Molecular Dynamics Simulation Study of Bromelain as Anti-SARS-CoV-2 Variants

2021 ◽  
Vol 12 ◽  
Author(s):  
Trina Ekawati Tallei ◽  
Fatimawali ◽  
Afriza Yelnetty ◽  
Rinaldi Idroes ◽  
Diah Kusumawaty ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Three Dimensional ◽  
Md Simulations ◽  
Inhibitory Effect ◽  
Dynamics Simulation ◽  
Novel Coronavirus

The rapid spread of a novel coronavirus known as SARS-CoV-2 has compelled the entire world to seek ways to weaken this virus, prevent its spread and also eliminate it. However, no drug has been approved to treat COVID-19. Furthermore, the receptor-binding domain (RBD) on this viral spike protein, as well as several other important parts of this virus, have recently undergone mutations, resulting in new virus variants. While no treatment is currently available, a naturally derived molecule with known antiviral properties could be used as a potential treatment. Bromelain is an enzyme found in the fruit and stem of pineapples. This substance has been shown to have a broad antiviral activity. In this article, we analyse the ability of bromelain to counteract various variants of the SARS-CoV-2 by targeting bromelain binding on the side of this viral interaction with human angiotensin-converting enzyme 2 (hACE2) using molecular docking and molecular dynamics simulation approaches. We have succeeded in making three-dimensional configurations of various RBD variants using protein modelling. Bromelain exhibited good binding affinity toward various variants of RBDs and binds right at the binding site between RBDs and hACE2. This result is also presented in the modelling between Bromelain, RBD, and hACE2. The molecular dynamics (MD) simulations study revealed significant stability of the bromelain and RBD proteins separately up to 100 ns with an RMSD value of 2 Å. Furthermore, despite increases in RMSD and changes in Rog values of complexes, which are likely due to some destabilized interactions between bromelain and RBD proteins, two proteins in each complex remained bonded, and the site where the two proteins bind remained unchanged. This finding indicated that bromelain could have an inhibitory effect on different SARS-CoV-2 variants, paving the way for a new SARS-CoV-2 inhibitor drug. However, more in vitro and in vivo research on this potential mechanism of action is required.

Molecular Dynamics Simulation of Neutron Damage in β-SIC

1998 ◽  
Vol 540 ◽  
Author(s):  
J.M. Perlado ◽  
L. Malerba ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Point Defects ◽  
Damage Accumulation ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Temperature Sensitive ◽  
Neutron Damage ◽  
Preliminary Study ◽  
Threshold Displacement

AbstractMolecular Dynamics (MD) simulations of neutron damage in β-SiC have been performed using a modified version of the Tersoff potential. The Threshold Displacement Energy (TDE) for Si and C atoms at 300 K has been determined along directions [001], [110], [111] and [ 1 1 1 ]. The existence of recombination barriers, which allow the formation of metastable, temperature-sensitive defects even below the threshold, has been observed. Displacement cascades produced by both C- and Si-recoils of energies spanning from 0.5 keV up to, respectively, 5 keV and 8 keV have also been simulated at 300 K and 1300 K. Their analysis, together with the analysis of damage accumulation (∼3.4×10-3 DPA) at 1300 K, reveals that the two sub-lattices exhibit opposite responses to irradiation: whereas only a little damage is produced on the “ductile” Si sub-lattice, many point-defects accumulate on the much more “fragile” C sub-lattice. A preliminary study of the nature and clustering tendency of these defects is performed. The possibility of disorder-induced amorphization is considered and the preliminary result is that no amorphization takes place at the dose and temperature simulated.

Influence of Carbon Nanotube Aspect Ratio on Glass Transition Temperature of Polymers: A Molecular Dynamics Simulation Study

2015 ◽  
Vol 817 ◽  
pp. 797-802 ◽  
Author(s):  
Cai Jiang ◽  
Jian Wei Zhang ◽  
Shao Feng Lin ◽  
Su Ju ◽  
Da Zhi Jiang
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Aspect Ratio ◽  
Epoxy Resin ◽  
Md Simulations ◽  
Diglycidyl Ether ◽  
Dynamics Simulation

Molecular dynamics (MD) simulations on three single walled carbon nanotube (SWCNT) reinforced epoxy resin composites were conducted to study the influence of SWCNT type on the glass transition temperature (Tg) of the composites. The composite matrix is cross-linked epoxy resin based on the epoxy monomers bisphenol A diglycidyl ether (DGEBA) cured by diaminodiphenylmethane (DDM). MD simulations of NPT (constant number of particles, constant pressure and constant temperature) dynamics were carried out to obtain density as a function of temperature for each composite system. The Tg was determined as the temperature corresponding to the discontinuity of plot slopes of the densityvsthe temperature. In order to understand the motion of polymer chain segments above and below the Tg, various energy components and the MSD at various temperatures of the composites were investigated and their roles played in the glass transition process were analyzed. The results show that the Tg of the composites increases with increasing aspect ratio of the embedded SWCNT

A Molecular Dynamics Simulation Study of the Mechanical Properties of Carbon-Nanotube Reinforced Polystyrene Composite

2014 ◽  
pp. 466-477
Author(s):  
Nabila Tahreen ◽  
K. M. Masud
Keyword(s):  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Longitudinal Direction ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Minimization Method ◽  
Polymer Properties ◽  
Polystyrene Matrix ◽  
Nanotube Composites ◽  
Strain Energy Minimization

In recent years, polymer/carbon nanotube composites have attracted increased attention because the polymer properties have significantly improved. In this paper, a single walled carbon nanotube (SWCNT) is used to reinforce polystyrene matrix. Molecular dynamics (MD) simulations are used to study two periodic systems - a long CNT-reinforced polystyrene composite and amorphous polystyrene matrix itself. The axial and transverse elastic moduli of the amorphous polystyrene matrix and nanocomposites are evaluated using constant-strain energy minimization method. The results from MD simulations are compared with corresponding rule-of-mixture predictions. The simulation results show that CNTs significantly improve the stiffness of polystyrene/CNT composite, especially in the longitudinal direction of the nanotube. Polystyrene posses a strong attractive interaction with the surface of the SWCNT and therefore play an important role in providing effective adhesion. The conventional rule-of-mixture predicts a smaller value than MD simulation where there are strong interfacial interactions. Here the authors report a study on the interfacial characteristics of a CNT-PS composite system through MD simulations and continuum mechanics.

Sign in / Sign up

Export Citation Format

Share Document