Mandal Taraknath, Dasgupta Chandan, Maiti Prabal K
Centre for Condensed Matter Theory, Physics Department, Indian Institute of Science, Bangalore-560012, India.
J Chem Phys. 2014 Oct 14;141(14):144901. doi: 10.1063/1.4897160.
We have performed fully atomistic classical molecular dynamics simulations to calculate the effective interaction between two polyamidoamine dendrimers. Using the umbrella sampling technique, we have obtained the potential of mean force (PMF) between the dendrimers and investigated the effects of protonation level and dendrimer size on the PMF. Our results show that the interaction between the dendrimers can be tuned from purely repulsive to partly attractive by changing the protonation level. The PMF profiles are well-fitted by the sum of an exponential and a Gaussian function with the weight of the exponential function dominating over that of the Gaussian function. This observation is in disagreement with the results obtained in previous analytic [C. Likos, M. Schmidt, H. Löwen, M. Ballauff, D. Pötschke, and P. Lindner, Macromolecules 34, 2914 (2001)] and coarse-grained simulation [I. Götze, H. Harreis, and C. Likos, J. Chem. Phys. 120, 7761 (2004)] studies which predicted the effective interaction to be Gaussian.
我们进行了全原子经典分子动力学模拟，以计算两个聚酰胺胺树枝状大分子之间的有效相互作用。使用伞形抽样技术，我们获得了树枝状大分子之间的平均力势（PMF），并研究了质子化水平和树枝状大分子大小对PMF的影响。我们的结果表明，通过改变质子化水平，树枝状大分子之间的相互作用可以从纯粹的排斥性调整为部分吸引性。PMF曲线可以很好地用指数函数和高斯函数之和拟合，其中指数函数的权重超过高斯函数。这一观察结果与先前的分析[C. Likos, M. Schmidt, H. Löwen, M. Ballauff, D. Pötschke, and P. Lindner, Macromolecules 34, 2914 (2001)]和粗粒化模拟[I. Götze, H. Harreis, and C. Likos, J. Chem. Phys. 120, 7761 (2004)]研究结果不一致，后者预测有效相互作用为高斯型。
