摘要
用分子动力学模拟研究了铆接于带电固体壁面上的两性无规共聚电解质链的构型及其随溶剂的介电常数、系统温度和带电壁面电场的变化。结果表明,聚离子链的构型取决于外电场对链节的作用、链内各链节间的静电作用和链节的热运动(温度)三者的综合作用结果。电场强度较低时,铆接聚离子链与非铆接聚离子链的构型变化类似。电场强度较高时,两性聚离子链构型更为舒展。溶剂介电常数减小,链节间静电作用增强,净电荷比较小的中性或非中性两性聚电解质链倾向于收缩,净电荷比较多的链则膨胀。温度的升高一般总是抵消电场和分子内静电作用的影响,当它占主导地位时将使聚离子链膨胀。
Configuration of polyampholyte attached on a charged solid surface were simulated by molecular dynamics(MD) method. The influences of the dielectric constant of different solvents, temperature and external electric field intensity were also investigated. The simulated results indicate that the configurations of polyampholyte chain are effected by the external field, net charge of polyampholyte and temperature. At lower external field, the configurations of the attached polyampholyte chain are similar to that of a non-attached polyampholyte. At high external field, the polyampholyte chain is more extended. When solvent dielectric constant decreases, the intramolecular electrostatic effect increases, neutral polyampholyte or non-neutral polyampholyte with lesser net charges will be inclined to shrink, while non-neutral polyampholyte with more net charges may be extended. Rising temperature will counteract the influences of external field and intramolecular electrostatic effect on the configuration. When the thermal motion of sengments is in dominative, the polyampholyte chain is usually in swelling states.
出处
《功能高分子学报》
CAS
CSCD
2004年第3期377-384,共8页
Journal of Functional Polymers
基金
国家自然科学基金(N0.20025618
20236010)
上海市高校网络技术E-研究院(200303)
上海市教委资助项目