非传统晶体生长的早期观察

Early stages of non-classic crystal growth

晶体早期生长的研究揭示,在某些体系中,晶体生长可能并不遵循传统路径.借由某些聚合物或生物分子的帮助,无机晶体的前驱体或纳米晶体在生长初期有可能聚集为无序的大块颗粒.这些聚集体表面晶化形成高结晶度高密度的外壳,随后完成从表面到核心的晶化过程.此逆向晶体生长机理在一些诸如沸石、钙钛矿、金属和金属氧化物等无机化合物体系中均已被发现,在其他材料体系里也将得到验证.认识这一新的晶体生长路径将给予我们更多的自由度来实现晶体形态控制,也有助于我们对于许多天然矿物形成机制的理解.本文简要回顾了最近本领域研究中一些典型逆向晶体生长的例子.

Investigation of early stages of crystal growth revealed that crystal growth in some systems may not follow the classic route.In the early stages of inorganic crystal growth,precursor molecules and/or nanocrystallites may aggregate into large and disordered particles with the assistance of some polymers or biomolecules.Surface crystallization of these aggregates would then take place to form shells with high crystallinity and density,followed by an extension of the crystallization from surface to core.This so-called reversed crystal growth mechanism has been found in crystallization of several inorganic compounds including zeolites,perovskites,metals and metal oxides,and will be identified in more material systems.The establishment of this new crystal growth route gave us more freedom to control the morphology of crystals and to understand the formation mechanism of many natural minerals.This article gives a brief review of the recent research in this field by featuring some typical examples of the reversed crystal growth.