Paquay Stefan, Both Gert-Jan, van der Schoot Paul
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Physics Department, Brandeis University MS057, 415 South Street, Waltham, Massachusetts 02453, USA.
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Phys Rev E. 2017 Jul;96(1-1):012611. doi: 10.1103/PhysRevE.96.012611. Epub 2017 Jul 31.
When colloidal particles form a crystal phase on a spherical template, their packing is governed by the effective interaction between them and the elastic strain of bending the growing crystal. For example, if growth commences under appropriate conditions, and the isotropic crystal that forms reaches a critical size, growth continues via the incorporation of defects to alleviate elastic strain. Recently, it was experimentally found that, if defect formation is somehow not possible, the crystal instead continues growing in ribbons that protrude from the original crystal. Here we report on computer simulations in which we observe both the formation of ribbons at short interaction ranges and packings that incorporate defects if the interaction is longer-ranged. The ribbons only form above some critical crystal size, below which the nucleus is disk-shaped. We find that the scaling of the critical crystal size differs slightly from the one proposed in the literature, and we argue that this is because the actual morphology transition is caused by the competition between line tension and elastic stress, rather than the competition between chemical potential and elastic stress.
当胶体颗粒在球形模板上形成晶相时，它们的堆积受颗粒间有效相互作用以及生长晶体弯曲时的弹性应变控制。例如，如果在适当条件下开始生长，形成的各向同性晶体达到临界尺寸后，生长会通过引入缺陷来缓解弹性应变而继续进行。最近，实验发现，如果无法以某种方式形成缺陷，晶体反而会在从原始晶体突出的条带中继续生长。在此，我们报告计算机模拟结果，我们观察到在短程相互作用下条带的形成，以及在长程相互作用下包含缺陷的堆积。条带仅在某个临界晶体尺寸以上形成，低于该尺寸时核呈盘状。我们发现临界晶体尺寸的标度与文献中提出的略有不同，我们认为这是因为实际的形态转变是由线张力和弹性应力之间的竞争引起的，而不是化学势和弹性应力之间的竞争。
