A_a型Patchy胶体粒子的相态结构

根据热力学微扰理论研究了Aa型Patchy胶体的相态结构,考察了Patch之间的缔合强度及Patch数目对体系相态结构的调控机制.利用相平衡原理给出了Patchy胶体的流体、玻璃态固体和面心立方晶体之间转变及溶胶-凝胶转变的相图,讨论了玻璃态和晶态固相的成核机制、临界现象和相变问题.研究结果表明,Patchy胶体粒子之间的缔合作用和Patch数目可以显著地调控体系的三相点、临界温度和临界密度等特征.在高温条件下,Patchy胶体以一次成核方式结晶;而在低温条件下则以两步成核方式逐步成核结晶,中间经过非晶态的玻璃态固相作为过渡.说明Patchy粒子之间的缔合作用对其相态结构具有决定性影响,因而成为调控体系聚集态结构的重要因素.

Phase Structure of A a Type of Patchy Colloids

Phase structure of Aa type of Patchy colloids was presented under various conditions by the principle of phase equilibrium, where the phases of fluid(F), random close packing(RCP) and face centered cubic ( FCC ) were investigated to give the corresponding phase diagrams for F-F, F-RCP and F-FCC transitions, as well as for the sol-gel transition. It is shown that the crystallization of the Patchy colloid at a relatively high temperature is subjected to a one-step nucleation mechanism, and at a relatively low temperature it is subjected to a two-step nucleation mechanism companied with a metastable glassy state. An attempt is made to illustrate how the association strength and the number of patches regulate the phase state of Patchy particles, in particular, for glassy and crystal states. As a result, a significant effect of the two factors on the critical temperature, triple point, critical density and phase structure were found. Moreover, a relationship between the sol-gel and F-F transitions was also considered.