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Distinct Viscoelasticity of Hierarchical Nanostructures Self-Assembled from Multiblock Copolymers
Macromolecules ( IF 5.1 ) Pub Date : 2020-12-02 , DOI: 10.1021/acs.macromol.0c02096
Wei Hong 1 , Jiaping Lin 1 , Xiaohui Tian 1 , Liquan Wang 1
Affiliation  

We employed a nonequilibrium dissipative particle dynamics method to study viscoelastic properties of hierarchical lamellar structures self-assembled from heptablock copolymers. Three ways of shearing with respect to lamellar planes, including parallel, vertical, and transverse shearing, were imposed to study the viscoelasticity of ordered systems. In parallel shear, with the morphology transformation from disorder to general lamellae to parallel lamellae-in-lamella, both the storage and loss moduli of multiblock copolymer melt show a remarkable improvement. In addition to the parallel lamellae-in-lamella, the multiblock copolymers can form perpendicular lamellae-in-lamella with different viscoelastic behaviors. In vertical shear, parallel lamellae-in-lamella shows terminal behavior, while a low-frequency plateau in the storage modulus exists for the perpendicular lamellae-in-lamella. In transverse shear, the storage moduli for both perpendicular and parallel lamellae-in-lamellae with strong separation of small-length-scale structure exhibit a solid-like plateau at low frequency. The physical origin underlying the distinct viscoelasticity of various hierarchical lamellae was revealed by monitoring the motions of polymer blocks at different length scales. The present work could provide information for preparing advanced materials based on packed lamellae.

中文翻译:

由多嵌段共聚物自组装的分层纳米结构的独特粘弹性

我们采用非平衡耗散粒子动力学方法来研究由七嵌段共聚物自组装的分层层状结构的粘弹性质。研究层状平面的三种剪切方式,包括平行剪切,垂直剪切和横向剪切,以研究有序系统的粘弹性。在平行剪切中,随着从无序层到普通层到平行层内层的形态转变,多嵌段共聚物熔体的储能模量和损失模量均显示出显着改善。除了平行的层合片外,多嵌段共聚物还可以形成具有不同粘弹性行为的垂直的层合片。在垂直剪切条件下,平行薄层中的薄层显示出最终行为,垂直片中片的储能模量处于低频平稳状态。在横向剪切中,垂直和平行薄层中的薄层具有很强的小长度尺度结构分离的储能模量在低频下呈现出固态的平台。通过监测聚合物嵌段在不同长度尺度上的运动,揭示了各种分层薄片独特的粘弹性的物理起源。本工作可为基于填充薄片的高级材料制备提供信息。通过监测聚合物嵌段在不同长度尺度上的运动,揭示了各种分层薄片独特的粘弹性的物理起源。本工作可为基于填充薄片的高级材料制备提供信息。通过监测聚合物嵌段在不同长度尺度上的运动,揭示了各种分层薄片独特的粘弹性的物理起源。本工作可为基于填充薄片的高级材料制备提供信息。
更新日期:2020-12-22
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