Institute for Computational Physics, University of Stuttgart, Allmandring 3, D-70569 Stuttgart, Germany.
Institute for Nano- and Microfluidics, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, D-64287 Darmstadt, Germany.
J Chem Phys. 2017 Jul 21;147(3):034902. doi: 10.1063/1.4993619.
We use mesoscopic lattice-Boltzmann/molecular dynamics simulations to study the stretching behavior of a single tethered polymer in micro- and nanochannels. In particular, we are interested in the connection between fluid flow properties and the force on the polymer chain. An analytical expression for the stretching force is proposed, which linearly depends on the number of monomers and the boundary shear rate. In agreement with theory, the numerical findings reveal that the influence of hydrodynamic interactions can be ignored, which is also supported by results of additional Langevin dynamics simulations. Our simulation data coincide with the analytical expression for the fractional extension of the chain and further indicate that even weak Poiseuille flow profiles induce a strong alignment of the chain along the channel walls. The numerical results are in good agreement with experimental data obtained by microfluidic stretching of tethered λ-DNA.
我们使用介观格子玻尔兹曼/分子动力学模拟来研究微纳米通道中单个束缚聚合物的拉伸行为。特别是，我们感兴趣的是流体流动性质和聚合物链上的力之间的关系。我们提出了一个拉伸力的解析表达式，该表达式与单体数量和边界剪切速率呈线性关系。与理论一致，数值结果表明可以忽略流体动力学相互作用的影响，这也得到了额外的朗之万动力学模拟结果的支持。我们的模拟数据与链的分数延伸的解析表达式相符，进一步表明，即使是微弱的泊肃叶流型也会导致链沿着通道壁强烈对齐。数值结果与通过束缚 λ-DNA 的微流控拉伸获得的实验数据吻合良好。
