Computer Simulations on Mechanical Properties of Molecular Deposition Film

2005 ◽  
Vol 475-479 ◽  
pp. 3665-3668 ◽  
Author(s):  
Hui Qing Lan ◽  
Decai Li ◽  
Si Wei Zhang

The mechanical properties of the molecular deposition film deposited on an Au substrate are studied in the theory for the first time. Firstly, the quantum mechanics have been used to calculate the structure parameters and potential parameters of the molecular deposition film. Secondly, molecular dynamics simulations have been used to study indent process of the molecular deposition film with the action of Au tip. The results showed that an obvious jump to contact appears during the Au tip approaches the molecular deposition film; furthermore, the tilt angle and load of the molecules near the tip have the same tendency of hysteresis, which may be caused by the adhesive force between the tip and the molecular deposition film.

Author(s):  
Toshihiro Kaneko ◽  
Kenji Yasuoka ◽  
Ayori Mitsutake ◽  
Xiao Cheng Zeng

Multicanonical molecular dynamics simulations are applied, for the first time, to study the liquid-solid and solid-solid transitions in Lennard-Jones (LJ) clusters. The transition temperatures are estimated based on the peak position in the heat capacity versus temperature curve. For LJ31, LJ58 and LJ98, our results on the solid-solid transition temperature are in good agreement with previous ones. For LJ309, the predicted liquid-solid transition temperature is also in agreement with previous result.


2013 ◽  
Vol 4 ◽  
pp. 429-440 ◽  
Author(s):  
Hlengisizwe Ndlovu ◽  
Alison E Ashcroft ◽  
Sheena E Radford ◽  
Sarah A Harris

We examine how the different steric packing arrangements found in amyloid fibril polymorphs can modulate their mechanical properties using steered molecular dynamics simulations. Our calculations demonstrate that for fibrils containing structural defects, their ability to resist force in a particular direction can be dominated by both the number and molecular details of the defects that are present. The simulations thereby suggest a hierarchy of factors that govern the mechanical resilience of fibrils, and illustrate the general principles that must be considered when quantifying the mechanical properties of amyloid fibres containing defects.


Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 440 ◽  
Author(s):  
Aaron Liu ◽  
Qing Peng

Graphene is one of the most important nanomaterials. The twisted bilayer graphene shows superior electronic properties compared to graphene. Here, we demonstrate via molecular dynamics simulations that twisted bilayer graphene possesses outstanding mechanical properties. We find that the mechanical strain rate and the presence of cracks have negligible effects on the linear elastic properties, but not the nonlinear mechanical properties, including fracture toughness. The “two-peak” pattern in the stress-strain curves of the bilayer composites of defective and pristine graphene indicates a sequential failure of the two layers. Our study provides a safe-guide for the design and applications of multilayer grapheme-based nanoelectronic devices.


RSC Advances ◽  
2016 ◽  
Vol 6 (33) ◽  
pp. 28121-28129 ◽  
Author(s):  
Yanan Xu ◽  
Mingchao Wang ◽  
Ning Hu ◽  
John Bell ◽  
Cheng Yan

The mechanical properties of titanium dioxide (TiO2) nanotubes are studied based on molecular dynamics simulations.


2011 ◽  
Vol 10 (03) ◽  
pp. 359-370 ◽  
Author(s):  
JUAN PANG ◽  
HU YANG ◽  
JING MA ◽  
RONGSHI CHENG

Poly(N-alkylacrylamide) is a group of thermo-sensitive polymers that include poly (N-isopropylacrylamide), poly(N-n-propylacrylamide), poly(N-isopropylmethacryl-amide), and so on. The polymers exhibit different levels of lower critical solution temperatures (LCST) in aqueous solutions. In this article, their monomers and oligomers with 10 repeating units are selected, respectively, to demonstrate the cause of different LCST levels of the polymers in aqueous solutions using molecular dynamics simulations and quantum mechanics calculations. The monomers have functional groups of different steric volume that greatly affect the conformational transition of chains and LCST levels of the polymers. A branched chain of N-propyl group in N-isopropylacrylamide and an additional methyl group at α-carbon in N-isopropylmethacrylamide both increase the steric effect, making it more difficult for monomers to draw closer and resulting in higher LCST levels of the polymers. In addition, the simulated results from their corresponding oligomers exhibit the similar trend to those from the monomers.


Sign in / Sign up

Export Citation Format

Share Document