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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。
Polyelectrolytes are a kind of typical soft material, which combines the dual characteristics of polymer and electrolyte. It has wide application prospect in the fields of drug delivery, fuel cell membrane and nano-coating. Unlike neutral polymers, polyelectrolytes must account for long-range electrostatic interactions during phase separation. The aqueous solution of triblock polyelectrolytes with different concentrations was simulated based on the average field dynamic density functional theory and the electrostatic interactions were dealt with using local neutral conditions. By changing the polyelectrolyte concentration, some typical phase structures such as lamellar phase, bicontinuous phase, hexagonal columnar phase, spherical micelles and the like are obtained. In order to study the polyelectrolyte solution in a confined space phase behavior, different concentrations of polyelectrolyte solution into the hole for simulation. The results show that when the charge of the block is changed, the system can form a stack of disks, single spiral and hole-like layered ordered microstructures. In addition, the order structure obtained in the confined space is gradually destroyed as the power of the block increases, eventually disappearing. By defining the order parameter of the hydrophobic block, the order-disorder transition critical charge of each concentration polyelectrolyte solution system was determined. Some results obtained in this work will be of some guidance to the research work of new nanomaterials.