Molecular Dynamic and Mesoscopic Dynamic Simulations for Polymer Blends

2014 ◽  
Vol 1033-1034 ◽  
pp. 496-500 ◽  
Author(s):  
Min Zhang ◽  
Guo Fang Zhang ◽  
Yu Xi Jia
Keyword(s):  
Free Energy ◽  
Energy Density ◽  
Polymer Blends ◽  
Free Energy Density ◽  
Md Simulations ◽  
Solubility Parameters ◽  
Dynamic Simulations ◽  
Density Profiles ◽  
Huggins Parameter ◽  
Phase Separation Behavior

The compatibilities of polymer blends, Polypropylene (PP) and Polyamide12(PA12) with the quantity ratio 10/90, was simulated by Molecular Dynamics (MD) and Mesoscopic Dynamic simulation (MesoDyn) simulations. Cohesive energy density (CED) and solubility parameters (δ) of pure substances and PP/PA12 blends were got by MD simulations. Flory-Huggins parameter was calculated based on CED values. The mesoscale simulation was related to the molecular simulation through Flory-Huggins parameter. Free energy density and the density profiles were got through MesoDyn simulation. Results showed that solubility parameter difference (Δδ) of PP/PA12 is 4.092 and free energy density value is 0.17 in the equivalent system. And phase separation behavior was observed in the density profiles. All these indicates that PP and PA12 is not miscible which is the same as the experiment results.

Mesoscale Simulations of the Polymer Blends Based on the Mesoscopic Dynamic Method

2014 ◽  
Vol 633-634 ◽  
pp. 234-237
Author(s):  
Min Zhang ◽  
Guo Fang Zhang ◽  
Yu Xi Jia
Keyword(s):  
Free Energy ◽  
Phase Separation ◽  
Energy Density ◽  
Polymer Blends ◽  
Dynamic Method ◽  
Free Energy Density ◽  
Order Parameters ◽  
Mesoscale Simulation ◽  
Density Profiles ◽  
Phase Separation Behavior

The mesoscale simulation of polymer blends, Polypropylene (PP) and Polyamide12 (PA12), was calculated by Mesoscopic Dynamic method (MesoDyn). The free energy density, the order parameters and the density profiles were got by the simulation. The evolvement of the phase status was analyzed based on the free energy density and the order parameters. Using density profiles, the kinetics of phase separation was examined and the phase separation behavior was observed. Results showed that mesoscale simulation can be used to determine phase separation of sparingly miscrible polymer blends.

Molecular Dynamic Simulations on the Compatibility of PP/PA12 Blends

2014 ◽  
Vol 633-634 ◽  
pp. 270-273 ◽  
Author(s):  
Min Zhang ◽  
Guo Fang Zhang ◽  
Yu Xi Jia
Keyword(s):  
Molecular Dynamics ◽  
Polymer Blends ◽  
Md Simulation ◽  
Md Simulations ◽  
Solubility Parameters ◽  
Molecular Dynamic Simulations ◽  
Dynamic Simulations ◽  
Cohesive Energy Density ◽  
Pure Substances ◽  
The Difference

The compatibilities of polymer blends, Polypropylene (PP) and Polyamide12(PA12), was simulated by molecular dynamics (MD) simulations. Density, cohesive energy density (CED) ,and solubility parameters (δ) of pure substances and PP/PA12 blends were calculated by MD simulations with the COMPASS force field for the prediction of polymer blends compatibility . Results showed that PP/PA12 is not miscrible by comparing the difference in the solubility parameter value ( Δδ), radial distribution function value. The predictions agreed well with the experimental results. So it can be showed that MD simulation is a valid method to provide information on miscibility of polymer blends.

On nematic surface energies

1997 ◽  
Vol 8 (3) ◽  
pp. 293-299 ◽  
Author(s):  
SANDRO FAETTI ◽  
EPIFANIO G. VIRGA
Keyword(s):  
Free Energy ◽  
Liquid Crystal ◽  
Energy Density ◽  
Continuum Theory ◽  
Free Energy Density ◽  
Optic Axis ◽  
Principal Curvatures ◽  
Equilibrium Equations ◽  
Line Integral ◽  
Surface Energies

We review the main outcomes of a continuum theory for the equilibrium of the interface between a nematic liquid crystal and an isotropic environment, in which the surface free energy density bears terms linear in the principal curvatures of the interface. Such geometric contributions to the energy occur together with more conventional elastic contribution, leading to an effective azimuthal anchoring of the optic axis, which breaks the isotropic symmetry of the interface. The theory assumes the interface to be fixed, as for a rigid cavity filled with liquid crystal, and so it does not apply to drops. It should be appropriate when the curvatures of the interface are small compared to that of the molecular interaction sphere. Also, interfaces bearing a sharp edge are encompassed within the theory; a line integral expresses the energy condensed along the edge: we see how it affects the equilibrium equations.

scholarly journals Fluctuations and phase transitions of uniaxial and biaxial liquid crystals using a theoretically informed Monte Carlo and a Landau free energy density

2019 ◽  
Vol 31 (17) ◽  
pp. 175101
Author(s):  
Stiven Villada-Gil ◽  
Viviana Palacio-Betancur ◽  
Julio C Armas-Pérez ◽  
Juan J de Pablo ◽  
Juan P Hernández-Ortiz
Keyword(s):  
Monte Carlo ◽  
Free Energy ◽  
Phase Transitions ◽  
Liquid Crystals ◽  
Energy Density ◽  
Free Energy Density ◽  
Landau Free Energy ◽  
Biaxial Liquid Crystals
Sign in / Sign up

Export Citation Format

Share Document