frictional coefficient, f in polymer chemistry, in polymer crystals

https://dx.doi.org/10.1351/goldbook.F02528
A tensor correlating the frictional force, F, opposing the motion of a particle in a viscous fluid and the velocity u of this particle relative to the fluid. In the case of an isolated spherical particle in a viscous isotropic fluid, f is a constant and F = f u.
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