Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India.
J Chem Phys. 2019 Jan 28;150(4):044708. doi: 10.1063/1.5053974.
Molecular dynamics simulations of Lennard-Jones particles have been performed to study the self-assembled structure of nanoparticles (NPs) formed upon evaporation of nanofluid droplets on a heated surface. Different shapes of NPs such as a sphere, cube, triangle, and rod are considered in this work for the nanofluid. The influence of solvent-surface and NP-surface interaction strengths, size, and shape of NPs is analyzed on the structure of the NP deposit formed upon evaporation. The solvophilic substrate leads to the formation of different structures such as the hemispherical clump, monolayer, and ring depending on the size, shape, and interaction between other pairs of atoms. On the other hand, the solvophobic substrate always leads to a clump of NPs. Structural and thermodynamic properties are calculated to characterize the self-assembled structures. The low pair energy and high excess entropy are the characteristics of a ring structure. Furthermore, the mean square displacement of NPs is found to be lower for the ring structure compared to the hemispherical clump structure, and this observation is independent of the shape and size of the NP. The change in arrangement from disorder to order is observed for rod shaped NPs during evaporation.
采用分子动力学模拟方法研究了在加热表面上纳米流体液滴蒸发时形成的纳米颗粒（NPs）的自组装结构。在这项工作中，考虑了不同形状的 NPs，如球体、立方体、三角形和棒体，作为纳米流体。分析了溶剂-表面和 NP-表面相互作用强度、NP 的尺寸和形状对蒸发后 NP 沉积物结构的影响。亲溶剂衬底会导致不同结构的形成，如半球形团簇、单层和环，这取决于其他原子对之间的大小、形状和相互作用。另一方面，疏溶剂衬底总是会导致 NP 团簇的形成。通过计算结构和热力学性质来表征自组装结构。低对能和高过剩熵是环结构的特征。此外，与半球形团簇结构相比，环结构的 NPs 均方位移较小，这种观察结果与 NP 的形状和尺寸无关。在蒸发过程中，棒状 NPs 的排列从无序到有序发生变化。
