Facile equilibration of well-entangled semiflexible bead-spring polymer melts

The widely used double-bridging hybrid (DBH) method for equilibrating simulated entangled polymer melts [Auhl et al., J. Chem. Phys. 119, 12718-12728 (2003)] loses its effectiveness as chain stiffness increases into the semiflexible regime because the energy barriers associated with double-bridging Monte Carlo moves become prohibitively high. Here we overcome this issue by combining DBH with the use of core-softened pair potentials. This reduces the energy barriers substantially, allowing us to equilibrate melts with N & SIME; 40N(e) and chain stiffnesses all the way up to the isotropic-nematic transition using simulations of no more than 100 x 10(6) time steps. For semiflexible chains, our method is several times faster than the standard DBH; we exploit this speedup to develop improved expressions for Kremer-Grest melts' chain-stiffness-dependent Kuhn length l(K) and entanglement length N-e.

Automated summary

The widely used double-bridging hybrid method for equilibrating simulated entangled polymer melts loses effectiveness as chain stiffness increases. By combining the double-bridging hybrid method with core-softened pair potentials, the energy barriers can be reduced substantially, allowing for more efficient equilibration of polymer melts with increasing chain stiffness.