L-半胱氨酸自组装膜诱导草酸钙结晶研究

在CaCl2.H2O和Na2C2O4配制的过饱和溶液中,利用L-半胱氨酸(L-Cys)在金片上形成的自组装膜为模板,研究了草酸钙(CaOxa)在自组装膜上的结晶行为,并探讨了溶液pH对CaOxa晶体组成、晶型及其形貌的影响。采用X射线衍射(XRD)和扫描电子显微镜(SEM)等技术对CaOxa晶体的结构和形貌进行了表征。实验结果表明:当溶液pH=3.0时,溶液中可以形成一水草酸钙(CaC2O4.H2O,COM)和二水草酸钙(CaC2O4.2H2O,COD)晶体,而在同样pH条件下,在L-Cys自组装膜上只形成COD晶体,表明自组装单层对CaOxa晶体的成核和生长有重要影响。通过改变溶液的pH,在自组装单层上可以得到不同晶型和不同形状的CaOxa晶体。当pH=3.0时得到四方块状的COD晶体,而pH=5.0和pH=7.0时分别得到六边形和拉长六边形的COM晶体。

Crystallization of Calcium Oxalate on the Self-assembled Monolayer of L-Cysteine

In order to study the interaction between the organic molecules and calcium oxalate crystals, the self-assembled monolayer of L-cysteine was used as the template to induce the crystallization of calcium oxalate. The calcium oxalate crystals obtained from the solution and on the monolayer of L-cysteine were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Experimental results indicated that the self-assembled monolayer of L-Cys has a strong impact on the crystallization of CaOxa. Various crystal morphotogies such as square, hexagon, elongated hexagon were obtained. With the increase of the solution pH, the crystals obtained on the monolayer of L-Cys were shifted from calcium oxalate dihydrate at pH=3.0 to calcium oxalate hydrate at pH=7.0.