ClayPolymers Nanocomposite Project

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Clay/Polymers Nanocomposite Project

• QMUL, June 27-28 2002

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Contents

• Monte Carlo simulations
• Nanocomposite systems
• Methodology
• Results
• Mechanical Properties
• Methods
• Models
• Results
• LAMMPS
• Validation of the Teppens force field
  implementation
• New parameters for the acrylate function
• Scaling and timing properties

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Monte Carlo Simulations

• Nanocomposite systems

PEG3diacrylate (288 g/mol)
PEG3diamine (220 g/mol)
PEG7diamine (510 g/mol)
PEG7diacrylate (484 g/mol)
PPG3diamine and PEG3dimethacrylate (316
g/mol) PEG3dimethacrylate and PEG3diglycidylether
(262 g/mol)
Ethylenediamine and formaldehyde (60 g/mol)
(30 g/mol)
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• Methodology
• Competitive adsorptions of the monomers
• Generation of conformers
• 250 conformers generated by a Boltzmann Jump
  method
• Selection of 4 conformers among the 250 ones
• two lowest radius of gyration (RoG)
• two highest RoG
• Monte Carlo
• Grand canonical ensemble (mPT)
• vapour pressure 0.001 kPa
• 10,000,000 steps

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• Results

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Mechanical Properties

• Methods
• Second derivative method
• properties derived from the second derivative of
  the energy
• Constant stress minimization
• minimization under constrains
• Constant strain minimization
• minimization keeping constant the lattice
  parameters
• Discover/OFF and steepest descent/Newton-Raphson
  
• Models
• PEG3acrylate nanocomposite
• PEG3diacrylate nanocomposite

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• Results

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LAMMPS

• Validation of the Teppens force field
  implementation
• Swelling of the Na/Montmorillonite clay
• Water system
• NaCl/Water system

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• Swelling of Na/Montmorillonite by H2O

100 ps, dt1 fs, NPT ensemble, 300 K
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• Water system
• Periodic cubic cell (19.8133x19.8133x19.8133 Å3)
• r1 g/mol
• 260 water molecules
• NVT ensemble, 300 K, 100 ps, dt1 fs

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• NaCl/Water system
• Periodic cubis cell (15.8236x15.8236x15.8236 Å3)
• r1 g/mol
• 100 water molecules 10 pairs of NaCl ions
• NVT ensemble, 300 K, 100 ps, dt1 fs

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• New parameters in the Teppens force field for
  the acrylate function
• CH2CHCO O R
• p system similar to that of the benzene molecule

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• Scaling and timing properties of LAMMPS
• systems
• PPG3diamine 6486 atoms, 1 ps and 20 ps, T3E,
  SGI3800
• PEG3acrylate1043 atoms, 1 ps, T3E, with and
  without rRESPA
• PEG3acrylate6258 atoms, 1ps, T3E, with and
  without rRESPA
• Acknowledgements to Shantenu

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