Thermal-induced crossover: Darcy-to-power law response in flow of polymer chains

Flow of polymer chains is studied as a function of temperature (T), field (E), and chain length (Lc) by a hybrid computer simulation. In low field, the polymer flow rate density ( j) shows a linear response, i.e., Darcy law, j=φE at high temperatures and a power-law response j=φEδ at low temperatures. The power-law response exponent, δ is nonuniversal and depends on temperature (δ 1.0–2.0). The chain permeability φ=A(Lc)T0.21±0.01 in the low temperature regime; the prefactor A(Lc) decays with the chain length according to A Lc−0.18.