水凝胶中KCl晶体的取向生长

Oriented Growth of KCl Crystals in Hydrogel

采用溶剂蒸发法在水凝胶介质中得到了KCl枝晶图案。利用扫描电子显微镜对晶体形态进行了表征。枝晶呈十字形,由大量具有小面形态的微晶颗粒平行聚集而成。在图案生长前沿区域,晶粒以{100}晶面在二维扩散场中沿着对角线方向伸展排列,体现出4mm对称特点,与KCl晶体自身点群m3m对称性相容。凝胶介质可以将间隔较远的晶粒联系起来,使晶体生长保持一致的取向。水凝胶介质不仅为晶体生长提供了受限微环境和成核位点,还对KCl晶体的取向生长产生重要的影响。

The dendritic patterns of KCl crystals were obtained in the hydrogel medium after the evaporation of solvent. The crystal morphology was characterized by Scanning Electron Microscope （SEM）. The cross-shaped dendrites were composed by many faceted crystallites in parallel aggregation form. In growth front of the patterns, the crystallites with the crystal face {100} were growing along the directions of the diagonals in the two-dimensional diffusional field, showing 4ram symmetry which is consistent with KCl crystal＇s point group m3m. There was a connection between the isolated single crystals via the gel matrix to keep the well oriented crystal alignment. The hydrogel medium not only provided the controlled microenvironment and nucleation sites, but also influenced greatly on the oriented growth of KCl crystals.