Tag: MD (Molecular Dynamics)

Tensile strength of polymer

Organic molecules, such as polymers or biopolymers can partly cover enormous tensile strengths. In the shown example of a graphene nanoflake, which has been tested on tensile strength, it has been more than 250 times bigger than for steel!

This strong property shall be used in a composit material, to substantially change its properties compared to the pure material.
The strength of the molecule has its origin in the chemical bond. Material cracks do not open normally within molecules, but between molecules. Therefore the intermolecular forces are an important part of the models. It is possible, to check virtually polymers or its composits on the tensile strength without knowing the macroscopic material properties in advance.

 

Let identify material properties in advance

Let identify material properties online now, before synthesis or production, simple and less expensive!

  • density in [kg/m3]
  • viscosity (shear viscosity) in [N·s/m2]
  • heat capacity in [kJ/mol/K]
  • thermal conductivity (assumption: isotropic) in [kJ/m/K/s]
  • diffusion coefficient in [cm2/s]
  • compressibility (isothermal) in [kJ/mol/l]
  • elasticity module in [kN/mm2]

Order here: xirrus simulation matters

 

xirrus GmbH simulates surface coatings with Molcular Dynamics

In an MD simulation of a hydrophobic brush layer on a pure metal surface one can investigate in direct comparison where water and other substances are distributed under the chosen conditions. The study of longer sequences allows to derive the thermodynamic equilibrium (mean preferred location) as well as the dynamics (diffusion: how fast are sites exchanged).

Hydrophobic coatings can be applied by hydrophobic substances, e.g. so called brush layers. Mostly they are bound chemically after they have been brought to the surface, such that wear of the molecular brushes is low. Those who never have seen such a simulation model by their own eyes, would be surprised by the quick motions, that quick that only little measuring methods could capture them at all.
A simple measure for the quality of the brush layer is the contact angle of an applied water droplet. The more it comes close to 180 degrees, the more hydrophobic the surface is.