Rouse Mode Analysis of Relaxation in Polymer Blends

• Published in: Macromolecular theory and simulations Vol. 30; no. 2
• Main Authors: Li, Wei, Cao, Xue‐Zheng, Merlitz, Holger, Wu, Chen‐Xu
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-03-2021
• Subjects: Composite materials; Composition; Dependence; Dynamic mechanical properties; Electrophoretic mobility; Ferries; Mechanical properties; Molecular dynamics; Monomers; Physical properties; Polymer blends; Polymers; relaxation dynamics; Rheological properties; Rheology; rouse mode analysis
• ISSN: 1022-1344; 1521-3919
• DOI: 10.1002/mats.202000084

The relaxation spectra of the components in polymer blends determine the dynamic mechanical properties of the corresponding composite materials, which, in thermo‐rheological studies, show a delicate dependence on their chemical and physical properties as well as its bulk composition. A molecular dynamics simulation based Rouse mode analysis is performed to detect the relaxation spectra of the component chains on all length scales ranging from one monomer to the whole chain size, indicating that the bulk composition dominates the relaxation dynamics of the components in miscible polymer blends. The relaxation of component chains accelerates on all length scales as increasing the free volume available to monomers to move, with the dependence of mobility shift on composition being quantified by a Williams–Landel–Ferry like function governing the time‐composition superposition. Role of the chain connectivity induced self‐concentration effect on chain relaxation in polymer blends is discussed and proved to be limited, which leads to a visible but subtle length‐scale dependent rheological complexity as the composition is varied.
Rouse mode analysis performed to detect the relaxation spectra of chains on full length scales up to the whole chain size, demonstrates that the bulk composition governed dynamical environment dominates the relaxation dynamics of components in miscible polymer blends. A Williams–Landel–Ferry like function is presented and verified to quantify the dependence of mobility shift of involved components on composition.