三嵌段聚电解质水溶液在圆柱受限空间内的相行为  

Phase behaviors of Polyelectrolyte solutions under cylindrical confinement

作　　者：刘铁驹[1] 陈倩[1] 郝清海[1] 牛晓辉[1] 苗兵[2] 

机构地区：[1]中国民航大学理学院,天津300300 [2]中国科学院大学材料科学与光电技术学院,北京100049

出　　处：《计算机与应用化学》2015年第8期907-911,共5页Computers and Applied Chemistry

基　　金：国家自然科学基金资助项目(21104094);中央高校基本科研业务费理学专项(3122013k003)

摘　　要：聚电解质是一种典型的软物质,兼具聚合物与电解质的双重特征,在药物输送、燃料电池膜、纳米涂覆等方面的应用有着广泛的应用前景。不同于中性高分子,聚电解质在相分离过程中必须考虑长程的静电相互作用。基于平均场动态密度泛函理论,并采用局域电中性条件处理静电相互作用,对浓度不同的三嵌段聚电解质的水溶液进行了模拟计算。通过改变聚电解质浓度,一些典型的相结构,如层状相、双连续相、六角柱状相、球形胶束等被获得。为了研究聚电解质溶液在受限空间内的相行为,将不同浓度的聚电解质溶液放入圆孔内进行模拟。结果表明,当嵌段的电量发生改变,体系能够形成堆叠的圆盘、单螺旋、有洞的层状相等有序微观结构。此外,随着嵌段的电量增加,受限空间内得到的有序结构逐渐被破坏,最终消失。通过定义疏水嵌段的序参量,确定了各浓度聚电解质溶液体系的有序-无序转变临界电量。本工作得到的一些结果将对新型纳米材料的研究工作具有一定的指导意义。As typical soft matter, polyelectrolytes have both properties of copolymer and electrolyte, which have extensive applications in drug delivery, fuel cell membrane, nanocoating and so on. Based on mean-field dynamic density functional theory, the phase behavior of the polyelectrolyte solutions with different concentrations are investigated by applying the local electron-neutrality constraint to deal with long-range electrostatic interaction. By varying the concentration, the polyelectrolyte solutions in the bulk are self-assembled into the typical structures including the lamellae, the bi-continuous gyroids, the hexagonally-ordered cylinders, the spheres, and so on. In order to study the phase behavior of polyelectrolyte solutions under confinement, polyelectrolyte solutions with different concentrations are put into cylindrical pores. By increasing the charge of hydrophilic blocks, a series of ordered morphologies were observed, such as, the stacked disk, the single helix, and the perforated layer in our simulations. Besides, for solutions with different concentrations, the ordered phase structures will fade out for further increasing the charge. Furthermore, the critical order-disorder transition points are also determined by defining the order parameter of the hydrophobic segments. The results in this work will be instructive in some extent for the investigations in nanomaterials.

关 键 词：聚电解质 圆柱受限 自组装 平均场动态密度泛函理论 

分 类 号：TQ015.9[化学工程] TP391.9[自动化与计算机技术—计算机应用技术]