良溶剂中接枝型聚两性电解质单链构象的布朗动力学模拟

发布时间：2018-04-12 00:15

本文选题：布朗动力学模拟 + 接枝聚两性电解质　；参考：《高等学校化学学报》2016年03期

【摘要】：采用布朗动力学研究了在良溶剂中荷电平衡的接枝聚两性电解质(GPA)的单链构象转变行为,讨论了主链链长、支链数及电荷密度对GPA分子链构象转变的影响.研究发现,随着静电相互作用的增强,GPA分子链构象转变过程由线团、主链与支链间的折叠、链段塌缩和电荷配对形成偶极子与四极子等4个阶段构成.与线型聚两性电解质不同,GPA存在的额外支链间空间排斥与静电排斥作用随着分子结构的变化而改变,并影响构象转变行为.在强静电相互作用下,良溶剂中的GPA链由于溶剂化作用会再伸展,以保证偶极子完全配对成四极子.减小主链长度或电荷密度或增加支链数目都会增大体系的排斥力和主链的刚性,阻滞分子链的塌缩,并使得分子链再伸展的幅度增大.
[Abstract]:Brownian kinetics was used to study the single-strand conformation transition behavior of grafted amphiphilic electrolyte (GPA) with charge equilibrium in good solvent. The effects of chain length, branching chain number and charge density on the conformation transition of GPA molecular chain were discussed.It is found that with the enhancement of electrostatic interaction, the conformation transition of GPA molecular chains consists of four stages: the coils, the folding between main chains and branched chains, the collapse of segments and the formation of dipole and quadrupole by charge pair.Different from linear polyamphoteric electrolytes, the spatial repulsion and electrostatic repulsion between the extra branched chains of GPA changed with the change of molecular structure and affected the conformational transition behavior.Under the strong electrostatic interaction, the GPA chain in a good solvent will be restretched due to the solvation to ensure that the dipole is fully paired into a quadrupole.Decreasing the length or charge density of the main chain or increasing the number of the branched chains will increase the repulsive force and the rigidity of the main chain, block the collapse of the molecular chain, and increase the amplitude of the restretching of the molecular chain.
【作者单位】：华东理工大学材料科学与工程学院上海市先进聚合物材料重点实验室;
【基金】：国家自然科学基金(批准号:20974032)资助~~
【分类号】：O631.1

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