Wärmeleitfähigkeit von Polymer-Materialien durch Nichtgleichgewichts-Molekulardynamik-Simulation

• Antragsteller: Professor Dr. Florian Müller-Plathe
• Fachliche Zuordnung: Chemische und Thermische Verfahrenstechnik
• Förderung: Förderung von 2003 bis 2012
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 5406603

• Erstellungsjahr: 2012

Zusammenfassung der Projektergebnisse

Methods for the calculation by classical molecular dynamics simulations of the thermal conductivity, their predictive accuracies, and their application to molecular liquids, polymers, and carbon nanotubes (CNTs) have been developed and validated. Particular attention has been paid to the influence of simulation settings, size-effects, and force fields on the calculated thermal conductivity. The simulation parameters, such as the use of thermostat, exchange period in the algorithm, and atomic vs. molecular exchange, have the lowest impact on the calculated value. Variation of simulation parameters in reasonable ranges results in deviations the respective error bars only. Size effects can be avoided, but should be investigated for each system anew. For molecular liquids as well as for polymers, a simulation box of several nanometers length is sufficient, whereas for carbon nanotubes even several hundred nanometers are not enough. The choice of the force field appears to be most decisive for the calculated thermal conductivity. Correctly tuned united-atom models together with bond constraints lead to significant improvements in the prediction accuracy. A particular success of this project has been to understand quantitatively and qualitatively three phenomena associated with heat conduction in CNTs: (i) the break-down of Fourier's law, as the thermal conductivity is not a constant but depends on the length of CNTs; (ii) the thermal rectification, i.e. the thermal conductivity of an asymmetrically prepared CNT being different in both directions; (iii) the absence of the commonly expected massive increase of the thermal conductivity of polymer materials, when CNTs are mixed into them.

Projektbezogene Publikationen (Auswahl)

• A nonequilibrium molecular dynamics method for thermal conductivities based on thermal noise. Journal of Chemical Physics, Vol. 122. 2005, Issue 8, 081103.
  T. Terao and F. Müller-Plathe
  
• Comment on: A nonequilibrium molecular dynamics method for thermal conductivities based on thermal noise. Journal of Chemical Physics, Vol. 123. 2005, Issue 21 , 217101.
  T. Terao, F. Müller-Plathe
  
• Reverse non-equilibrium molecular dynamics calculation of the Soret coefficient in liquid benzene/cyclo¬hex¬ane mixtures. Journal of Chemical Physics, Vol. 123. 2005, Issue 12, 124502.
  M. Zhang F. Müller-Plathe
  
• Thermal Conductivities of Molecular Liquids by Reverse Non-equilibrium Molecular Dynamics. Journal of Physical Chemistry B, Vol. 109. 2005, Issue 31, pp. 15060–15067.
  M. Zhang, E. Lussetti, L.E.S. de Souza, F. Müller-Plathe
  
• The Soret effect in dilute polymer solutions: Influence of chain length, chain stiffness and solvent Quality. Journal of Chemical Physics, Vol. 125. 2006, Issue 12, 124903.
  M. Zhang and F. Müller-Plathe
  
• Non-equilibrium molecular dynamics calculation of the thermal conductivity of amorphous polyamide-6,6. Journal of Physical Chemistry B, Vol. 111. 2007, Issue 39, pp, 11516–11523.
  E. Lussetti, T. Terao, F. Müller-Plathe
  
• Non-equilibrium molecular dynamics methods for computing the thermal conductivity: Application to amorphous polymers. Physical Review E, Vol. 75. 2007, 057701.
  T. Terao, E. Lussetti, F. Müller-Plathe
  
• Thermal diffusion measurements and simulations of binary mixtures of spherical Molecules. Journal of Chemical Physics, Vol. 127. 2007, Issue 1, 014502.
  P. Polyakov, M. Zhang, F. Müller-Plathe, S. Wiegand
  
• Reverse nonequilibrium molecular dynamics calculation of the Soret coefficient in liquid heptane/benzene mixtures. Journal of Physical Chemistry B, Vol. 112. 2008, Issue 47, pp. 14999–15004.
  P. Polyakov, F. Müller-Plathe, S. Wiegand
  
• Anisotropy of the thermal conductivity in a crystalline polymer: Non-equilibrium molecular dynamics simulation of the δ phase of syndiotactic polystyrene. Journal of Chemical Physics, Vol. 130. 2009, Issue 13, 134905.
  E. Rossinsky, F. Müller-Plathe
  
• Anisotropy of the Thermal Conductivity of Stretched Amorphous Polystyrene in Supercritical Carbon Dioxide Studied by Reverse Nonequilibrium Molecular Dynamics Simulations. Journal of Physical Chemistry B, Vol.113. 2009, Issue 44, pp. 14596–14603.
  E. A. Algaer, M. Alaghemandi, M. C. Böhm, F. Müller-Plathe
  
• The Thermal Conductivity and Thermal Rectification of Carbon Nanotubes Studied Using Reverse Non-equilibrium Molecular Dynamics Simulations. Nanotechnology, Vol. 20. 2009, Number 11, 115704.
  M. Alaghemandi, E. Algaer, M. C. Böhm, F. Müller-Plathe
  
• Thermal Conductivity of Amorphous Polystyrene in Supercritical Carbon Dioxide Studied by Reverse Non-Equilibrium Molecular Dynamics Simulations. Journal of Physical Chemistry A, Vol. 113. 2009, Issue 43, pp. 11487–11494.
  E. Algaer, M. Alaghemandi, M. C. Böhm, F. Müller-Plathe
  
• Thermal rectification in mass-graded nanotubes: a model approach in the framework of reverse non-equilibrium molecular dynamics simulations. Nanotechnology, Vol. 21. 2010, Number 7, 075704.
  M. Alaghemandi, F. Leroy, E. Algaer, M. C. Böhm, F. Müller-Plathe
  
• Thermal rectification in nanosized model systems: A molecular dynamics Approach. Physical Review B, Vol. 81. 2010, Iss. 12, 125410.
  M. Alaghemandi, F. Leroy, F. Müller-Plathe, M. C. Böhm
  
• Correlation between thermal conductivity and bond length alternation in carbon nanotubes: A combined reverse nonequilibrium molecular dynamics - Crystal orbital analysis. Journal of Computational Chemistry, Vol. 32. 2011, Issue 1, pp. 121–133.
  M. Alaghemandi, J. Schulte, F. Leroy, F. Müller-Plathe, M. C. Böhm
  
• Heat Transport through a Biological Membrane – an Asymmetric Property? Technical Issues of Non-equilibrium Molecular Dynamics Methods. International Journal of Quantum Chemistry, Vol. 111. 2011, Issue 7-8, pp. 1403–1418.
  T. J. Müller, F. Müller-Plathe
  
• Thermal Conductivity of a Carbon Nanotube – Polyamide-6,6 Composite: Reverse Nonequilibrium Molecular Dynamics Simulations. Journal of Chemical Physics, Vol. 135. 2011, Issue 18, 184905.
  M. Alaghemandi, M. C. Böhm, F. Müller-Plathe
  
• Molecular Dynamics Calculations of the Thermal Conductivity of Molecular Liquids, Polymers, and Carbon Nanotubes. Soft Materials, Vol. 10. 2012, Issue 1-3, pp. 42-80.
  E. A. Algaer, F. Müller-Plathe