Bertrand M, Slater G W
Department of Physics, University of Ottawa, 150 Louis-Pasteur, Ottawa, Ontario, Canada.
Eur Phys J E Soft Matter. 2007 May;23(1):83-9. doi: 10.1140/epje/i2007-10179-2. Epub 2007 May 30.
For a polyelectrolyte undergoing electrophoretic motion, it is predicted (D. Long, J.L. Viovy, A. Ajdari, Phys. Rev. Lett. 76, 3858 (1996); D. Long, A. Ajdari, Electrophoresis 17, 1161 (1996)) that the mechanical force necessary to stall the molecule is substantially smaller than the sum of electrical forces applied on all monomers. In fact, it should be proportional to its hydrodynamic friction coefficient and therefore to the size of its conformation. In our work we examine this prediction using coarse-grained molecular-dynamics simulations in which we explicitly include the polymer, the solvent, the counterions and salt. The electrophoretic mobility of polyelectrolytes is evaluated, the mechanical force necessary to keep the molecules tethered is measured and the resulting anisotropic polymer conformations are observed and quantified. Our results corroborate Long et al.'s prediction.
对于经历电泳运动的聚电解质，据预测（D. Long、J.L. Viovy、A. Ajdari，《物理评论快报》76，3858 (1996)；D. Long、A. Ajdari，《电泳》17，1161 (1996)），使分子停止运动所需的机械力远小于施加在所有单体上的电力之和。实际上，它应与其流体动力学摩擦系数成正比，因此也与它构象的大小成正比。在我们的工作中，我们使用粗粒度分子动力学模拟来检验这一预测，在模拟中我们明确纳入了聚合物、溶剂、抗衡离子和盐。评估了聚电解质的电泳迁移率，测量了使分子固定所需的机械力，并观察和量化了由此产生的各向异性聚合物构象。我们的结果证实了Long等人的预测。
