我们研究纳米粒子(NP)分散,聚合物构象,离子纳米复合材料中的缠结和动力学。为此,我们研究了具有各种球形NP负载的纳米复合材料系统,三种不同的分子量,两种不同的Bjerrum长度,和两种类型的电荷测序聚合物通过分子动力学模拟。由于静电相互作用的存在,NP分散可以在低聚或缠结的聚合物基质中实现。我们表明,离子低聚物链的整体构象,以它们的回转半径为特征,受到收费NP的存在和数量的影响,而带电缠结聚合物的尺寸保持不受干扰。聚合物和NP的动力学行为,以及临时交联的寿命和数量,发现取决于Bjerrum长度与带电单体之间的特征距离之间的比率。聚合物-聚合物缠结开始减少超过一定的NP负载。离子NP和聚合物的动力学与其非离子对应物相比非常不同。具体来说,离子NP动力学在纠缠矩阵中得到增强,并且随着NP负载的增加而加速。
We investigate nanoparticle (NP) dispersion, polymer conformations,
entanglements and dynamics in ionic nanocomposites. To this end, we
study nanocomposite systems with various spherical NP loadings, three different molecular weights, two different Bjerrum lengths, and two types of charge-sequenced polymers by means of molecular dynamics simulations. NP dispersion can be achieved in either oligomeric or entangled polymeric matrices due to the presence of electrostatic interactions. We show that the overall conformations of ionic oligomer chains, as characterized by their radii of gyration, are affected by the presence and the amount of charged NPs, while the dimensions of charged entangled polymers remain unperturbed. Both the dynamical behavior of polymers and NPs, and the lifetime and amount of temporary crosslinks, are found to depend on the ratio between the Bjerrum length and characteristic distance between charged monomers. Polymer-polymer
entanglements start to decrease beyond a certain NP loading. The dynamics of ionic NPs and polymers is very different compared with their non-ionic counterparts. Specifically, ionic NP dynamics is getting enhanced in entangled matrices and also accelerates with the increase of NP loading.