scholarly journals Penetration of Chitosan into the Single Walled Armchair Carbon Nanotubes: Atomic Scale Insight

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1174
Author(s):  
Jamoliddin Razzokov ◽  
Kamoladdin Saidov ◽  
Olim Ruzimuradov ◽  
Shavkat Mamatkulov
Keyword(s):  
Carbon Nanotubes ◽  
Nanocomposite Materials ◽  
Umbrella Sampling ◽  
Water Desalination ◽  
Atomic Scale ◽  
Valuable Insight ◽  
Free Energies ◽  
Penetration Process ◽  
Dynamics Simulations ◽  
Insight Into

(1) Background: Currently, nanomaterials have been broadly used in various applications including engineering, medicine and biology. One of the carbon allotropes such as carbon nanotubes (CNTs) implemented for fabrication of nanocomposite materials due to the hypersensitivity. The combined design of nanomaterial with chitosan (CS) and CNT expands the field of exploitation from biosensing and tissue engineering to water desalination. Therefore, the penetration of CS into CNT provides a valuable insight into the interactions between CS and CNT. (2) Methods: We performed molecular dynamics simulations, applying the umbrella sampling method, in order to calculate the potential mean force between CS and CNT. (3) Results: The estimated penetration free energies showed that CS is favorable to the penetration into CNT cavities. However, the penetration nature differs depending on the CNT’s architecture. (4) Conclusions: Our finding revealed the CS penetration process into CNT with nanoscale precision. The investigation results assist in a better understanding of the nanocomposite materials based on CS-CNT.

Atomic-scale simulations of radiation effects in GaN and carbon nanotubes

2003 ◽  
Vol 792 ◽  
Author(s):  
K. Nordlund ◽  
J. Nord ◽  
A. V. Krasheninnikov ◽  
K. Albe
Keyword(s):  
Carbon Nanotubes ◽  
Radiation Effects ◽  
Ion Irradiation ◽  
Research Community ◽  
Atomic Scale ◽  
High Radiation ◽  
Wide Range ◽  
Basic Physics ◽  
Materials Research ◽  
Dynamics Simulations

ABSTRACTGallium nitride and carbon nanotubes have received wide interest in the materials research community since the mid-1990's. The former material is already in use in optoelectronics applications, while the latter is considered to be extremely promising in a wide range of materials. Common to both materials is that ion irradiation may be useful for modifying their properties. In this paper we overview our recent molecular dynamics simulations results on ion irradiation of these materials. We employ such potentials to study the basic physics of how ion irradiation affects these materials. In particular we discuss the reasons for the high radiation hardness of GaN, and the surprising nature of vacancies and interstitials in carbon nanotubes.

Water desalination by electrical resonance inside carbon nanotubes

2016 ◽  
Vol 18 (40) ◽  
pp. 28290-28296 ◽  
Author(s):  
Jia-wei Feng ◽  
Hong-ming Ding ◽  
Yu-qiang Ma
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulations ◽  
Underlying Mechanism ◽  
Water Desalination ◽  
Electrical Resonance ◽  
New Type ◽  
Dynamics Simulations

By using molecular dynamics simulations, we not only design one new type of carbon nanotube-based device for efficient water desalination, but also reveal the underlying mechanism of the ion blockage.

Computational insight into the mechanisms of action and selectivity of Afraxis PAK inhibitors

2020 ◽  
Vol 12 (5) ◽  
pp. 367-385
Author(s):  
Di Han ◽  
Huiqun Wang ◽  
Wei Cui ◽  
Beibei Zhang ◽  
Bo-Zhen Chen
Keyword(s):  
Molecular Dynamics ◽  
Mechanisms Of Action ◽  
Structural Basis ◽  
Free Energies ◽  
Activity Data ◽  
Experimental Activity ◽  
Inhibitory Mechanisms ◽  
Dynamics Simulations ◽  
Insight Into ◽  
Binding Free Energies

Aim: The p21-activated kinases (PAKs) are involved in many important biological activity regulations. FRAX019, FRAX414, FRAX597, FRAX1036 and G-5555 were identified as PAKs inhibitors. Their detailed inhibitory mechanisms deserve further investigation. Results: Molecular dynamics simulations and further calculations for the PAK1/inhibitor and PAK4/inhibitor complexes indicate that their binding free energies are basically consistent with the trend of experimental activity data. Conclusion: The anchoring of residues Leu347PAK1 and Leu398PAK4 is the structural basis for designing Afraxis PAK inhibitors. This study discloses the inhibitory mechanisms of FRAX019, FRAX414, FRAX597, FRAX1036 and G-5555 toward PAK1 and PAK4 and some clues to enhance kinase activities and selectivities, which will provide valuable information to the development of more potent and selective PAK inhibitors.

Penetration of Hydrogen Into Alpha-Fe: A Molecular Dynamics Study

2017 ◽  
Author(s):  
Xiongying Li ◽  
Tiancheng Cui ◽  
Yongzhi Zhao ◽  
Jinyang Zheng ◽  
Ping Xu
Keyword(s):  
Molecular Dynamics ◽  
Simulation Method ◽  
Energy Difference ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Invasion Process ◽  
Hydrogen Atoms ◽  
Penetration Process ◽  
Hydrogen Penetration ◽  
Insight Into

Understanding of hydrogen penetration into α-Fe plays an important role in revealing the mechanism of hydrogen embrittlement in Fe-based alloys. This work aims to investigate the penetration process of hydrogen into α-Fe by molecular dynamics simulation method, including how hydrogen changes from molecular to atomic form and how hydrogen atoms enter into the sub-surface. Potential energy difference and atom density are calculated to describe the characteristics of H-Fe interactions and to analysis the invasion process. The simulation results provide an atomic-scale insight into the hydrogen invasion process.

scholarly journals Molecular origin of negative component of Helmholtz capacitance at electrified Pt(111)/water interface

2020 ◽  
Vol 6 (41) ◽  
pp. eabb1219
Author(s):  
Jia-Bo Le ◽  
Qi-Yuan Fan ◽  
Jie-Qiong Li ◽  
Jun Cheng
Keyword(s):  
Ab Initio Molecular Dynamics ◽  
Double Layers ◽  
Valuable Insight ◽  
Liquid Interfaces ◽  
Metal Electrodes ◽  
Physicochemical Processes ◽  
Colloid Science ◽  
Dynamics Simulations ◽  
Solid Liquid ◽  
Insight Into

Electrified solid/liquid interfaces are the key to many physicochemical processes in a myriad of areas including electrochemistry and colloid science. With tremendous efforts devoted to this topic, it is unexpected that molecular-level understanding of electric double layers is still lacking. Particularly, it is perplexing why compact Helmholtz layers often show bell-shaped differential capacitances on metal electrodes, as this would suggest a negative capacitance in some layer of interface water. Here, we report state-of-the-art ab initio molecular dynamics simulations of electrified Pt(111)/water interfaces, aiming at unraveling the structure and capacitive behavior of interface water. Our calculation reproduces the bell-shaped differential Helmholtz capacitance and shows that the interface water follows the Frumkin adsorption isotherm when varying the electrode potential, leading to a peculiar negative capacitive response. Our work provides valuable insight into the structure and capacitance of interface water, which can help understand important processes in electrocatalysis and energy storage in supercapacitors.

scholarly journals Ab InitioDensity Functional Theory Investigation of the Interaction between Carbon Nanotubes and Water Molecules during Water Desalination Process

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Loay A. Elalfy ◽  
Walid M. I. Hassan ◽  
Wael N. Akl
Keyword(s):  
Carbon Nanotubes ◽  
Reverse Osmosis ◽  
Molecular Orbital ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Water Desalination ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Dynamics Simulations

Density functional theory calculations using B3LYP/3-21G level of theory have been implemented on 6 carbon nanotubes (CNTs) structures (3 zigzag and 3 armchair CNTs) to study the energetics of the reverse osmosis during water desalination process. Calculations of the band gap, interaction energy, highest occupied molecular orbital, lowest unoccupied molecular orbital, electronegativity, hardness, and pressure of the system are discussed. The calculations showed that the water molecule that exists inside the CNT is about 2-3 Å away from its wall. The calculations have proven that the zigzag CNTs are more efficient for reverse osmosis water desalination process than armchair CNTs as the reverse osmosis process requires pressure of approximately 200 MPa for armchair CNTs, which is consistent with the values used in molecular dynamics simulations, while that needed when using zigzag CNTs was in the order of 60 MPa.

Compressive dynamic scission of carbon nanotubes under sonication: fracture by atomic ejection

2010 ◽  
Vol 467 (2129) ◽  
pp. 1270-1289 ◽  
Author(s):  
H. B. Chew ◽  
M.-W. Moon ◽  
K. R. Lee ◽  
K.-S. Kim
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Sheet ◽  
Atomic Scale ◽  
Tensile Fracture ◽  
Structural Peculiarity ◽  
Out Of Plane ◽  
Single Sheet ◽  
Dynamics Simulations ◽  
Flow Drag ◽  
Walled Carbon Nanotubes

We report that a graphene sheet has an unusual mode of atomic-scale fracture owing to its structural peculiarity, i.e. single sheet of atoms. Unlike conventional bond-breaking tensile fracture, a graphene sheet can be cut by in-plane compression, which is able to eject a row of atoms out-of-plane. Our scale-bridging molecular dynamics simulations and experiments reveal that this compressive atomic-sheet fracture is the critical precursor mechanism of cutting single-walled carbon nanotubes (SWCNTs) by sonication. The atomic-sheet fracture typically occurs within 200 fs during the dynamic axial buckling of a SWCNT; the nanotube is loaded by local nanoscale flow drag of water molecules caused by the collapse of a microbubble during sonication. This is on the contrary to common speculations that the nanotubes would be cut in tension, or by high-temperature chemical reactions in ultrasonication processes. The compressive fracture mechanism clarifies previously unexplainable diameter-dependent cutting of the SWCNTs under sonication.

scholarly journals Mechanical characterization and induced crystallization in nanocomposites of thermoplastics and carbon nanotubes

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Eduardo R. Cruz-Chú ◽  
Gonzalo J. Villegas-Rodríguez ◽  
Tobias Jäger ◽  
Luca Valentini ◽  
Nicola M. Pugno ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Rational Design ◽  
Mechanical Characterization ◽  
Experimental Tests ◽  
Nanocomposite Materials ◽  
Polyether Ether Ketone ◽  
Computational Workflow ◽  
Ether Ketone ◽  
Dynamics Simulations ◽  
Induced Crystallization

Abstract Nanocomposites built from polymers and carbon nanotubes (CNTs) are a promising class of materials. Computer modeling can provide nanoscale views of the polymer–CNT interface, which are much needed to foster the manufacturing and development of such materials. However, setting up periodic nanocomposite models is a challenging task. Here we propose a computational workflow based on Molecular Dynamics simulations. We demonstrate its capabilities and showcase its applications, focusing on two existing nanocomposite materials: polystyrene (PS) with CNT and polyether ether ketone with CNT. The models provide insights into the polymer crystallization inside CNTs. Furthermore, the PS+CNT nanocomposite models are mechanically tested and able to predict an enhancement in Young’s modulus due to the addition of highly dispersed CNTs. We accompany those results with experimental tests and provide a prediction model based on Dynamic Quantized Fracture Mechanics theory. Our study proposes representative simulations of polymer–CNT nanocomposites as promising tools to guide the rational design of this class of materials.

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