| |
[摘要]：Using recently developed analytical Green's function/numerical inverse Laplace transform methods, we calculate the hydrodynamic drag and confinement forces on a linear Gaussian chain inside an interacting and impenetrable cylindrical tube in the free draining limit. Equating the two forces leads to an estimation of the critical (minimum) flow rate (q(c)) to drag the chain through the tube. The estimated q(c) is compared with our measured q(c) in theta solutions as well as with our previous scaling argument for a variety of experimental conditions (solvent quality and tube radius, R). Satisfactory agreement between the calculated and observed critical flow rates reveals that the previous description by de Gennes of a linear chain confined in a tube as a series of hard spheres (blobs) significantly underestimates the hydrodynamic drag force, such that the predicted q(c) for the hard sphere model is 10(2)-10(3) times higher than observed. The calculations also confirm our previous scaling argument that q(c) decreases with increasing R, thus departing from the hard-sphere blob prediction that q(c) is independent of R. More importantly, the calculation describes how interactions with the tube walls affect chain confinement. |
|
