Session W18 - Computer Simulation II.
ORAL session, Thursday morning, March 15
Room 308-308, Washington State Convention Center
Monte Carlo simulations of linear and cyclic alkanes were performed on a coarse-grained high coordination lattice. The simulations were performed at 473 K for carbon numbers of 60, 100, and 316. The results indicated: (i) at low molecular weights (M), cyclic alkanes have lower diffusion coefficients (D) than linear alkanes, and (ii) at high M, they have higher D than linear alkanes. The lower D of the small cyclic alkanes was attributed to the high local density due within the volume defined by the smaller mean square radius of gyration of the cyclic alkanes. The high local density of cyclic alkane segments resulted in a decrease in the mobility of the beads. The crossover in D was observed around the entanglement weight of linear alkanes, which suggests that the linear alkanes are more susceptible to the effects of entanglements than are the cyclic alkanes.