Publications Details

What is the Entanglement Length in a Polymer Melt

Grest, Gary S.

We present the results of molecular dynamics simulations of very long model polymer chains analyzed by various experimentally relevant techniques. The segment motion of the chains is found to be in very good agreement with the reptation model. We also calculated the plateau modulus G⁰_N. The predictions of the entanglement length N_e from G⁰_N and from the mean square displacement of the chain segments disagree by a factor of about 2.2(2), indicating an error in the prefactor in the standard formula for G⁰_N. We show that recent neutron spin echo measurements were carried out for chain lengths which are too small to allow for a correct determination of N_e.