羟基磷灰石界面水行为的分子模拟

本文采用分子动力学模拟(MD)方法研究了羟基磷灰石(HAP)(001)和(100)晶面上的水分子行为，发现HAP晶面间的水是处在高电场和高内压的环境下，并可在晶面处形成2～3层高度结构化的水层，这些水具有有序结构和类冰固化特征。其中在HAP晶体的001]方向具有较强的极性，相对于100]方向能诱导产生更多的有序结构化水层。研究发现HAP-水界面处钙和磷酸根位点分布和水分子的吸附位点相关，并且水在HAP界面上的吸附形式具有多样性。该工作揭示了HAP界面结构化水层的形成及其结构细节特征。HAP晶面附近的结构化水层可阻止溶液离子自由出入晶面，对HAP颗粒在水溶液中的动力学稳定性具有重要的影响。

Molecular Simulation of Water Behaviors on Hydroxyapatite Crystal Faces

The water behaviors on the (100) and (001) crystal faces of HAP have been studied by using molecular dynamic simulations (MD). The results show that water molecules between the HAP faces are in a strong electrical field and high pressure environment and 2~3 well-organized water layers are formed on crystal surfaces. These structured water layers show ice-liked behaviors. Compared with crystallographical 100] direction of HAP, the polarity at the 001] direction is stronger, which could result in more structured-water layers. The interaction of water molecules with the calcium and phosphate sites has also been studied at the HAP-water interface. The interaction result indicates the multiple pathways of water adsorption onto the HAP surfaces. This study reveales the formation and the detailed structure of water layers on HAP surfaces, which plays an important role in kinetic stability of the HAP particles in aqueous solutions.