Coarse-grained force field for simulating polymer-tethered silsesquioxane self-assembly in solution
Coarse-grained force field for simulating polymer-tethered silsesquioxane self-assembly in solution
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DOI：
10.1063/1.2753493
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发表时间：
2007-09-21
影响因子：
4.4
通讯作者：
Glotzer, Sharon C.
中科院分区：
文献类型：
--
作者：
Chan, Elaine R.;Striolo, Alberto;Glotzer, Sharon C.
建立了一个模拟壬基笼型倍半硅氧烷（POSS）纳米粒子在溶液中自组装的粗粒模型。在粗粒度模型中，建立了原子分子中原子团到珠子的映射方案。粗粒力场由溶剂介导的有效相互作用势组成，这些相互作用势是通过基于结构的粗粒化数值迭代方案获得的。力场是由两种不同的迭代算法得到的。通过比较在粗粒化模型的模拟中观察到的POSS分子的聚集与在包含显式溶剂的全原子模拟中观察到的聚集来验证粗粒化方案。在300 K时，从不同的初始猜测得到的有效粗粒势是彼此可比的。在400 K时，从不同的初始猜测获得的力场之间的差异虽然很小，但很明显。使用不同的迭代算法，采用相同的初始猜测，导致在相同的整体有效的潜力裸立体角珠网站。在粗粒和全原子模拟中，观察到POSS分子的小聚集体具有类似的倍半硅氧烷笼和系链构象的局部堆积。粗粒度模型提供了大约两个数量级的计算时间节省。进一步的比较粗粒度的monotethered POSS模型在这里开发的最小模型在早期的工作。结果表明，POSS笼之间的相互作用是长程的，并捕获的粗粒度模型在这里开发。最小模型适用于捕获POSS立方体在短分离距离的局部分子间堆积。(c)2007年，美国物理学会。
A coarse-grained model has been developed for simulating the self-assembly of nonyl-tethered polyhedral oligomeric silsesquioxane (POSS) nanoparticles in solution. A mapping scheme for groups of atoms in the atomistic molecule onto beads in the coarse-grained model was established. The coarse-grained force field consists of solvent-mediated effective interaction potentials that were derived via a structural-based coarse-graining numerical iteration scheme. The force field was obtained from initial guesses that were refined through two different iteration algorithms. The coarse-graining scheme was validated by comparing the aggregation of POSS molecules observed in simulations of the coarse-grained model to that observed in all-atom simulations containing explicit solvent. At 300 K the effective coarse-grained potentials obtained from different initial guesses are comparable to each other. At 400 K the differences between the force fields obtained from different initial guesses, although small, are noticeable. The use of a different iteration algorithm employing identical initial guesses resulted in the same overall effective potentials for bare cube corner bead sites. In both the coarse-grained and all-atom simulations, small aggregates of POSS molecules were observed with similar local packings of the silsesquioxane cages and tether conformations. The coarse-grained model afforded a savings in computing time of roughly two orders of magnitude. Further comparisons were made between the coarse-grained monotethered POSS model developed here and a minimal model developed in earlier work. The results suggest that the interactions between POSS cages are long ranged and are captured by the coarse-grained model developed here. The minimal model is suitable for capturing the local intermolecular packing of POSS cubes at short separation distances. (c) 2007 American Institute of Physics.