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Materials Modeling for Polymer Simulation
QuantumATK polymer simulation software is used to design polymers with improved thermo-mechanical, thermal conductivity and optical properties within R&D of areas such as photoresist, transparent polymers, rubber-like polymers for tire industry and thermoset polymers for insulation industry.
Polymer building and equilibration tools in QuantumATK provide reliable polymer models, which can then be simulated using fully automated workflows, powered by a highly scalable MPI parallelized molecular dynamics (MD) engine.
Key advantages of QuantumATK
- Flexible and user-friendly GUI streamlining the building of various polymer systems while having full control of tacticity, monomer composition, and end groups
- Fully automated workflows for equilibrating and simulating polymer systems Simulations of extended time-scales through time-stamped force-bias Monte Carlo (TFMC) simulations
- Simulations of heat transport using the Reverse Non-Equilibrium Molecular Dynamics (RNEMD) methodology
- Advanced analysis tools in the GUI, such as a glass transition temperature analyzer, temperature profile for heat transport and others to advance polymer engineering
Fig 1: Polymer – Polymer Blend
Fig 2: Polymer - Inorganic Interface
Fig 3: Polymer - Nanoparticle Composite
Fully Automated Polymer Simulation Workflow
Builder
- Large ready-to-use monomer and end-group database; add custom monomers
- Interface to embed molecules, nanoparticles and surfaces
- Automatic assignment of connectivity tags to define monomer linking reactions
- Monte Carlo builder for polymer melts
- Tools for building polymers with cross-linked or 3D network structures
Parameter Setup
- Automatic potential generation for DREIDING, UFF and OPLS-AA
- More than 300 pre-defined parameter sets, including reactive ReaxFF potentials, parametrized for a wide range of organic and inorganic materials
- Charge equilibration using QEq and ReaxFF methods
Equilibration Methods
- Force-capped equilibration tools for initial equilibration
- Single-Chain Mean-Field (SCMF) equilibration
- Energy minimization for relaxing the polymer system
- 21 step polymer equilibration protocol
Fig 1:
Fig 2: Polymer simulation scripter
Fig 3: Polymer equilibration
Simulation Methods
- MD in the NVE, NVT, and NPT ensembles
- TFMC simulations for enhanced equilibration and simulating events over longer timescales
- RNEMD simulations of heat transport
- Automated calculation of stress-strain curves
Advanced Techniques
- Hook functions to implement customized simulation techniques and measurements in molecular dynamics
- Metadynamics simulations via interface to the PLUMED package
- United atoms and coarse-grained polymers to speed-up simulations
Analysis Tools
- Advanced analysis tools in the GUI, such as glass transition temperature analyzer, temperature profile for heat transport
- Interactive MD trajectory analysis and movie generation
- Highly flexible plotting framework for visualizing results (end-to-end distances, free-volume, characteristic ratio, etc.).
Application Examples
Stress-strain simulations (Young’s modulus)
Young’s modulus is obtained via a linear fit of the stress-strain curve calculated from stress-strain MD simulations, where the cell is strained at a constant rate in one direction at a time.
Example: Young’s modulus calculated for the photoresist co-polymer of two polymers: Poly[(4-[tert-butoxycarbonyl]oxy-styrene)-co-(4-vinylphenol)] as a function of deprotection of 4-vinylphenol monomer.
Glass transition temperature studies
Glass transition temperature, Tg, is obtained via using linear fitting to determine a discontinuity in the gradient of the density over temperature plot calculated from MD simulations.
Example: TG calculated for the poly(methyl methacrylate) (PMMA) polymer melt by cooling it from 550 K to 250 K temperature.
Thermal conductivity studies
Thermal conductivity is calculated from the temperature gradient due to non-equilibrium momentum exchange between heat sink and source regions in a polymer using RNEMD methodology.
Example: simulated thermal conductivity results for the poly(vinyl chloride) (PVC) polymer are in a good agreement with the experimental values, i.e., 0.14 W/mK vs 0.16 W/mK.
Optical properties
QuantumATK enables simulation and advanced analysis of a large range of optical and electro-optical parameters, such as Raman, infrared and optical spectrum, second harmonic generation susceptibility, electro-optical tensor.
Example: simulated optical spectrum of polyethylene (PE) based on i) the traditional chain of monomers model and ii) the more realistic polymer melt generated using QuantumATK polymer builder, which is in a better agreement with experimental results.
More Information
Learn more about QuantumATK products
Interested in applying QuantumATK software to your research? Test our software or contact us at quantumatk@synopsys.com to get more information on QuantumATK platform for atomic-scale modeling.