Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
Department of Chemical Engineering, University of Washington, Seattle, WA, 98195, USA.
Nat Commun. 2020 Feb 25;11(1):1045. doi: 10.1038/s41467-020-14719-w.
The interplay between crystal and solvent structure, interparticle forces and ensemble particle response dynamics governs the process of crystallization by oriented attachment (OA), yet a quantitative understanding is lacking. Using ZnO as a model system, we combine in situ TEM observations of single particle and ensemble assembly dynamics with simulations of interparticle forces and responses to relate experimentally derived interparticle potentials to the underlying interactions. We show that OA is driven by forces and torques due to a combination of electrostatic ion-solvent correlations and dipolar interactions that act at separations well beyond 5 nm. Importantly, coalignment is achieved before particles reach separations at which strong attractions drive the final jump to contact. The observed barrier to attachment is negligible, while dissipative factors in the quasi-2D confinement of the TEM fluid cell lead to abnormal diffusivities with timescales for rotation much less than for translation, thus enabling OA to dominate.
晶体和溶剂结构、颗粒间相互作用力以及整体颗粒响应动力学的相互作用控制了定向附着（OA）的结晶过程，但目前对此缺乏定量理解。我们以 ZnO 作为模型体系，将单个颗粒和整体组装动力学的原位 TEM 观察与颗粒间相互作用力和响应的模拟相结合，将实验得出的颗粒间势能与潜在相互作用联系起来。我们发现，OA 是由静电离子-溶剂相关性和偶极相互作用产生的力和力矩驱动的，这些相互作用的作用范围远远超过 5nm。重要的是，在颗粒达到强吸引力驱动最终接触跳跃的距离之前，颗粒就已经实现了准直。观察到的附着势垒可以忽略不计，而 TEM 流体室的准二维限制中的耗散因素导致异常的扩散率，其旋转时间远小于平移时间，从而使 OA 占据主导地位。
