原子力显微镜法研究方解石(104)面的生长及溶解

AFM Study of Calcite Growth and Dissolution on the (104) Face

研究生物矿化过程及生物矿物的形成机制具有重要的科学意义,这方面的研究不仅有助于我们认识自然,而且还可以指导体外仿生合成具有分级结构的功能性复合材料。原子力显微镜(atomic forcemicroscope,AFM)是微米、纳米尺度上实时观测矿物成核或生长的强有力工具。本文综述了原子力显微镜法研究方解石(104)面生长及溶解的最新进展,重点论述了有机添加剂对(104)面生长和溶解的影响,讨论了添加剂分子与方解石晶面间的作用方式和机制,为理解生物矿物的形成机理提供了新的启示。已有的研究表明,有机添加剂可通过与方解石(104)面的位点专一性作用改变晶体微粒从溶液相进入晶体相的能垒、台阶边缘自由能及(104)表面活性位的数目,从而改变台阶的生长动力学,以致影响晶体的整体形貌。最后,本文对今后方解石生物矿化的研究重点进行了展望。

Living organisms have evolved ability to produce biominerals or composites with exquisite structures and unique functionalities.Such a process is usually termed as biomineralization.Due to its high relevance to the fabrication of advanced materials,biomineralization has attracted tremendous interest in the past years.A comprehensive understanding of the biomineralization process and the underlying mechanism enables the biomimetic synthesis of functional materials with finely mediated structures.AFM is a powerful tool for in situ following the formation of biominerals at the micrometer and nanometer scale,particularly observing the crystal nucleation and growth.This paper reviews the recent advances in the AFM studies of calcite,focusing on the effects of organic additives on the growth and dissolution of the calcite（104） face.These organic additives include ethanol,carboxylic acids,amino acids,peptides,proteins and saccharides.Several proposed mechanistic interactions between organic additives and the（104） face are discussed.The documented investigations have indicated that step edge free energy,free energy barriers,and the number of active sites on surface can be tuned via site-specific interactions between organic additives and the crystal surface,thereby leading to the alteration of the step kinetics and the modification of the crystal morphology eventually.In the end,directions for future research in this regard are also discussed.