Molecular Dynamics Study of Tribological Behavior of Confined Branched and Linear Perfluoropolyethers
Molecular Dynamics Study of Tribological Behavior of Confined Branched and Linear Perfluoropolyethers
复制标题
限域支化和线性全氟聚醚摩擦学行为的分子动力学研究
DOI：
10.1021/jp984379b
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
A. Koike
中科院分区：
文献类型：
--
作者：
A. Koike
用分子动力学模拟方法研究了受限支化(Krytox型和Fomblin Y型)和线型(Demnum型和Fomblin Z型)全氟聚醚的流变行为。在所有情况下都观察到了粘度的剪切稀化，剪切稀释率与Demnum和Krytox类型的实验结果符合得很好。分支型Krytox型的粘度略低于线型Demnum型，尽管它们的体积粘性值相同。此外，观察到Demnum类型比Krytox类型具有更高的分子有序性。支链Fomblin Y型和线型Fomblin Z型具有较多的醚键，但没有观察到粘度差异。它们之间也没有观察到分子有序性差异。相应地，侧链效应预计会减弱，因为它们的许多醚键导致了分子的柔性。原子与其他原子之间的非键相互作用能。
Molecular dynamics simulations have been performed to study the rheological behavior of confined branched (Krytox type and Fomblin Y type) and linear (Demnum type and Fomblin Z type) perfluoropolyethers. Shear thinning of the viscosity is observed in all cases, and the shear thinning rate is in reasonable agreement with experimental results of Demnum and Krytox types. The viscosity of the branched Krytox type is slightly lower than that of the linear Demnum type when confined, although their bulk viscosity values are the same. Further, higher molecular ordering is observed in the Demnum type than in the Krytox type. However, no viscosity difference is observed between branched Fomblin Y and linear Fomblin Z types, which have many ether linkages. No molecular order difference is observed between them either. Accordingly, the side chain effect is expected to decrease because of the molecular flexibility caused by their many ether linkages. The nonbonded interaction energy between an atom and atoms of other ...