Jiro Sadanobu

The continuous configurational Boltzmann biased direct Monte Carlo method for free energy properties of polymer chains

We develop here a highly efficient variant of the Monte Carlo method for direct evaluation of the partition function, free energy, and other configurational dependent physical properties for long polymer chains. This method (CC–BB) combines continuous configurational biased sampling with Boltzmann factor biased enrichment. To illustrate the efficiency and to validate the bias correction for weighting the torsion and chain enrichments, we applied this model to isolated single chains using a united atom force field. For a 50 monomer polymer chain CC–BB with 400 chains leads to an accuracy of 0.1% in the free energy whereas simple sampling direct Monte Carlo requires about 109 chains for this accuracy. This leads to cost savings by a factor of about 350 000. CC–BB is easily extended to multichain systems, to the condensed state, to more realistic force fields, and to evaluating the mixing free energy for polymer blends.

Efficient Monte Carlo method for free energy evaluation of polymer chains

Abstract We have extended the Continuous Configuration Boltzmann Biased (CCBB) Monte Carlo method to predicting the free energy and properties of multiple-chain condensed amorphous polymers. We illustrate the method by considering two independent polyethylene (PE) chains per cell (each with 100 monomers) using periodic boundary conditions (PBC). In CCBB-MC the free energy is calculated directly and simultaneously with pressure and other configuration dependent properties. The phase transition from polymer vapor to liquid is demonstrated by the density dependence of pressure and free energy. At low temperature, increasing the density causes the chains to change from globular to interpenetrating due to increased screening. At high density, increasing the temperature causes each chain to shrink since it becomes more flexible due to the screened interchain interactions. This leads to a dramatically increased population of short lengths in the end-to-end distance distribution.

The Properties of Poly(Ethylene Naphthalate) (PEN) and its Application

TEIJIN Ltd. entered on the investigation of 2,6-naphthalene dicarboxilic acid (NDA) containing polymers in early 1960s. We have devoted a great deal of effort to the research and development toward its industrial application since then. Our research area has ranged from monomer synthesis to polymerization, fabrication processes and application technology. Finally we commercialized Poly(ethylene naphthalene) (PEN) in 1990 first in the world.

Gel-drawn Poly(p-phenylenepyromellitimide)

We have prepared high performance biaxially oriented PPPI film with high Young’s modulus. The film was converted from polyisoimde precursor oriented by gel-drawing. The gel-drawing process controls microstructure and morphology and results in break-through in overcoming intrinsic brittleness of long discarded material: PPPI. PPPI film with high Young’s modulus and excellent thermal stability is prospective material for next generation electronics use.