Combining the Langevin Dynamics method and the Computational Fluid Dynamics method, under the conditions of Knudsen number K-n <= 10(-1), we investigated the dynamics of a linear polymer transported into a channel of width D = 4 sigma embedded in two dimensions, driven by force-mimicked steady convergent microfluidics. We have proven that a critical volume-flow rate J(c) similar to k(B)T/eta similar to 1/eta exists in polymer transport, independent of chain length. Once the polymer has found the pore entrance in advance, we find that linear transport time, tau, is proportional to chain length N, but inversely proportional to volume-flow rate J; otherwise, if the polymer does not find the pore entrance in advance, we find that with regard to the linear transport probability, P, the law of P similar to N(0.25)J(c)exp(-k'/J) exists, where k' is a positive constant dependent only on channel geometry, friction coefficient and the position fixing polymer head outside the channel before the transport process starts, indicating that polymer initial conformations can affect the polymer transport probability.

Stretching and relaxation of a single DNA molecule tethered in a specially designed thin slit were studied using Monte Carlo simulation combined with bond-fluctuation method. It was found that the extension and relaxation of the single DNA molecule are greatly affected by the confined environment. If the extent of the confined environment is increased by decreasing the distance between the two planar surfaces of the slit, the extension of the single DNA molecule increases, due to the screening of the hydrodynamic interaction of DNA segments by the planar surfaces of the slit. The relaxation of the single DNA molecule in different confined environments verifies this assumption completely. The correlation between the end-to-end separation and flow velocity obtained by Monte Carlo simulation is in good agreement with either the experimental results or theoretical consideration reported previously.

The surface property of the viscometer could be changed dramatically by the monolayer of octadecyltrichlorosilane (OTS) via the hydrogen bonding on the wall surface. As a result, the original hydrophilic surface of the viscometer became hydrophobic. The flow time of the pure solvent, therefore, reduced from 120.69s to 118.78s. By measuring the contact angle of the pure water on the glass surface, together with the geometric parameter of the viscometer, the additional pressure originated from the curved surface of the liquid could be calculated. It was noted that the decrease of the flow time of the pure water did not originate from the change of the flow model of the fluid. In fact, the no-slip condition of the fluid was still satisfied on such an occasion.