Moghimikheirabadi Ahmad, Mugemana Clément, Kröger Martin, Karatrantos Argyrios V
Polymer Physics, Department of Materials, ETH Zurich, Leopold-Ruzicka-Weg 4, CH-8093 Zurich, Switzerland.
Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.
Polymers (Basel). 2020 Nov 4;12(11):2591. doi: 10.3390/polym12112591.
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.
我们研究了离子纳米复合材料中纳米颗粒（NP）的分散、聚合物构象、缠结和动力学。为此，我们通过分子动力学模拟研究了具有不同球形NP负载量、三种不同分子量、两种不同比耶鲁长度以及两种类型电荷序列聚合物的纳米复合体系。由于存在静电相互作用，NP可以在低聚物或缠结的聚合物基质中实现分散。我们表明，以回转半径为特征的离子低聚物链的整体构象会受到带电NP的存在和数量的影响，而带电缠结聚合物的尺寸则不受影响。发现聚合物和NP的动力学行为以及临时交联的寿命和数量都取决于比耶鲁长度与带电单体之间特征距离的比值。超过一定的NP负载量后，聚合物-聚合物缠结开始减少。与非离子型对应物相比，离子NP和聚合物的动力学非常不同。具体而言，离子NP动力学在缠结基质中得到增强，并且随着NP负载量的增加而加速。
