冰纳米晶体热力学参量的尺度和维度效应  

Size and dimensionality dependent thermodynamic properties of ice nanocrystals

作　　者：陆海鸣[1,2,3] 韩源源[1,2,3] 孟祥康[1,2,3] 

机构地区：[1]南京大学现代工程与应用科学学院,南京210093 [2]南京大学固体微结构物理国家重点实验室,南京210093 [3]南京大学-南通材料工程技术研究院,南京210093

出　　处：《科学通报》2013年第13期1242-1247,共6页Chinese Science Bulletin

基　　金：国家自然科学基金(11174120)资助

摘　　要：虽然冰的熔化是最常见的相变过程,但是对于(预)熔化和准液态表面层仍然存在许多争议,而且关于冰纳米晶体热力学参量与其尺度和维度之间关系的研究也很少.本文拓展建立了可描述氢键结合的冰纳米晶体熔化温度、预熔化温度和熔化焓的尺度和维度效应的理论模型.根据模型,上述热力学参量都随着尺度和维度的增加而增加,同时还发现预熔化温度和熔化温度具有几乎相同的尺度效应.模型对冰纳米粒子和纳米线的上述热力学参量尺度和维度效应的预测与相应的分子动力学模拟和实验结果相吻合,从而可以从理论上确定准液态层厚度.研究表明,准液态层厚度并不是恒定不变而是随着尺度的增加而缓慢增大,这也就是不同的研究报道中会出现不同准液态层厚度的原因.Although the melting of ice is the most ubiquitous phase transition,（pre）melting and quasi-liquid layer remain unclear and little is known about the relationship between the thermodynamic properties of ice nanocrystals and its size and dimensionality.Here,we model the size and dimensionality dependences of melting temperature,premelting temperature and melting enthalpy for hydrogen-bonded ice nanocrystals.These three thermodynamic parameters are found to increase with increasing size and dimensionality and the size dependence of premelting temperature almost follows the same trend as that of melting temperature.The models predictions are in agreements with available experimental and molecular dynamic simulation results of ice nanoparticles and nanowires.These agreements enable us to determine theoretically the quasi-liquid layer thickness,which is found to be not constant but slightly increase with increasing size and thus accounts for the occurrence of different reported thickness of quasi-liquid layer.

关 键 词：冰 熔化 预熔化 熔化焓 准液态层 尺寸效应 

分 类 号：TB383.1[一般工业技术—材料科学与工程]