Molecular flexibility effects upon liquid dynamics.
Simulation results for the diffusive behavior of polymer chain/penetrant systems are analyzed. The attractive range and flexibility of simple chain molecules were varied in order to gauge the effect on dynamics. In all cases, the dimensionless diffusion coefficient, D*, is found to be a smooth, single-valued function of the packing fraction, eta. The functions D*(eta) are found to be power laws with exponents that are sensitive to both chain stiffness and particle type. For a specific system type, the D*'s for both penetrant and chain-center-of-mass extrapolate to zero at the same packing fraction, eta0. This limiting packing fraction is interpreted to be the location of the glass transition, and (eta0-eta), the distance to the glass transition.
Heffernan
Julieanne V
JV
Department of Materials and Metallurgical Engineering, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA.
Budzien
Joanne
J
Wilson
Aaron T
AT
Baca
Robert J
RJ
Aston
Victoria J
VJ
Avila
Francisco
F
McCoy
John D
JD
Adolf
Douglas B
DB