## Abstract

Two alternative approaches are presented for evaluating the rotational diffusion constant D_{r} of entangled rodlike polymers in a semidilute solution. One is a quantitative refinement of the Doi-Edwards tube model, which gave for the first time a qualitative expression of D_{r}. To evaluate the mean square of a step angular displacement of the rodlike molecule, we use a computer simulation for Poisson line processes, while the mean lifetime of the tube is calculated by use of the first exit time of a stochastic process. The result is in good agreement with experimental data so far obtained. The other approach is a new Green function formulation on the dynamics of entangled rods; we regard the obstructions by neighbouring rods as a sequence of perturbation elements exerted on the free diffusion of the test rod. Incorporating the effects of the sequential perturbation one by one, we obtain an expression of D_{r} for rods in solutions in a wide range of concentrations from dilute to semidilute. In the semidilute region, this reduces to the result of the tube model.

Original language | English (US) |
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Title of host publication | Springer Series in Chemical Physics |

Publisher | Publ by Springer-Verlag New York |

Pages | 132-140 |

Number of pages | 9 |

Edition | 51 |

ISBN (Print) | 3540508295, 9783540508298 |

DOIs | |

State | Published - 1989 |

Event | Proceedings of the 11th Tanaguchi International Symposium - Hakone, Jpn Duration: Nov 7 1988 → Nov 12 1988 |

### Other

Other | Proceedings of the 11th Tanaguchi International Symposium |
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City | Hakone, Jpn |

Period | 11/7/88 → 11/12/88 |

## ASJC Scopus subject areas

- Physical and Theoretical Chemistry