不同化学官能团对无机相碳酸钙晶体的调控

Regulation of different functional groups on inorganic phase of calcium carbonate crystal

选择了具有代表性的化学官能团,羟基(—OH)、氨基(—NH2)、羧基(—COOH)和甲基(—CH3),通过在单晶硅片上进行接枝改性,并在改性后的硅基底上进行碳酸钙体外矿化模拟实验,以研究这些官能团对碳酸钙矿化的影响。利用接触角实验对接枝效果进行了分析,结果显示接枝成功。根据拉曼光谱(Raman)确定了碳酸钙的晶型;采用扫描电子显微镜(SEM)获得了碳酸钙的形貌、尺寸、数量和取向信息。结果显示羟基化硅基底上出现了方解石的聚集;氨基化硅基底和羧基化硅基底上均出现一定量的球文石,但形貌各异;甲基化硅基底上晶体数目较少。通过对结果的对比分析,认为羟基和甲基对碳酸钙的晶型选择无明显影响,氨基和羧基能通过对碳酸根离子或钙离子的吸附而诱导球文石结晶。

Several typical functional groups, -OH, -NH2, -COOH and -CH3 were selected in this work. In order to study the effect of the functional groups on calcium carbonate mineralization, the groups were grafted on single crystal silicon chips. The modified chips were used as substrates in the in vitro mineralization experiments. The contact angle was measured to examine the grafting efficiency, and the results showed that the groups were all successfully grafted. Raman was used to determine the crystal form. SEM was used to observe the morphology, size, quantity and orientation of calcium carbonate crystals. The results show that on -OH modified substrate, calcite aggregates are found, on -NH2 and -COOH modified substrates, some vaterites are found with different morphologies, on 1CH3 modified substrate, less crystals are found compared with the blank. It is supposed that -OH and -CH3 have no significant control effect over the polymorph of calcium carbonate crystals, -NH2 and -COOH can induce vaterite crystal growth bv absorbing CO^[2]3 or Ca^[2＋].