Institute of Physics, Johannes-Gutenberg University, D-55099 Mainz, Staudinger Weg 7, Germany.
J Chem Phys. 2010 Feb 21;132(7):074701. doi: 10.1063/1.3299001.
Confining a colloidal crystal within a long narrow channel produced by two parallel walls can be used to impose a mesoscale superstructure of a predominantly mechanical elastic character [Chui et al., EPL 83, 58004 (2008)]. When the crystal is compressed in the direction perpendicular to the walls, we obtain a structural transition when the number of rows of particles parallel to the walls decreases by one. All the particles of this vanishing row are distributed throughout the crystal. If the confining walls are structured (say with a corrugation along the length of the walls), then these extra particles are distributed neither uniformly nor randomly; rather, defect structures are created along the boundaries resembling "soliton staircases," inducing a nonuniform strain pattern within the crystal. Here, we study the conditions of stability, formation, and annihilation of these solitons using a coarse grained description of the dynamics. The processes are shown by comparing superimposed configurations as well as molecular animations obtained from our simulations. Also, the corresponding normal and shear stresses during the transformation are calculated. A study of these dynamical processes should be useful for controlling strain wave superstructures in the self-assembly of various nano- and mesoscaled particles.
将胶体晶体限制在两个平行壁之间形成的狭长通道中，可以用来施加主要具有机械弹性特征的介观超结构[Chui 等人，EPL 83, 58004（2008）]。当晶体沿垂直于壁的方向压缩时，当平行于壁的粒子行数减少 1 时，会发生结构转变。这个消失行的所有粒子都分布在整个晶体中。如果限制壁是结构化的（例如，沿着壁的长度具有波纹），那么这些额外的粒子不会均匀或随机分布；而是，在边界处会形成缺陷结构，类似于“孤子阶梯”，在晶体内部引起不均匀的应变模式。在这里，我们使用粗粒度描述动力学来研究这些孤子的稳定性、形成和湮灭条件。通过比较从模拟中获得的叠加构型和分子动画来展示这些过程。此外，还计算了在相变过程中的法向和剪切应力。对这些动力学过程的研究对于控制各种纳米和介观粒子自组装中的应变波超结构应该是有用的。
