Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
J Chem Phys. 2019 Feb 7;150(5):054903. doi: 10.1063/1.5064410.
The nucleation process of anisotropic particles often differs from that of their spherically symmetric counterparts. Despite a large body of work on the structure of droplets of anisotropic particles, their formation process remains poorly understood. In this study, homogeneous nucleation of uniaxial anisotropic particles was studied. Through structural analysis of cluster development and the formation free energy during the nucleation stage, it was revealed that the nucleation of uniaxial particles begins from highly ordered states. There is, however, a marked decrease in orientational order within the cluster before critical nucleus size is attained. Further investigation on variations in the molecular interactions demonstrates how droplet elongation and the direction of the nematic ordering director relative to the axis of elongation can both be controlled according to the nature of the molecular anisotropy.
各向异性颗粒的成核过程通常与它们的球对称对应物不同。尽管已有大量关于各向异性颗粒液滴结构的研究,但它们的形成过程仍未得到很好的理解。本研究中,对单轴各向异性颗粒的均相成核进行了研究。通过对簇发展的结构分析和成核阶段的形成自由能的研究,揭示了单轴颗粒的成核始于高度有序的状态。然而,在达到临界核大小之前,簇内的取向有序性明显降低。进一步研究分子相互作用的变化表明,液滴的伸长以及向列有序取向相对于伸长轴的方向都可以根据分子各向异性的性质来控制。