等温退火下链端修饰抑制短半晶聚合物片层增厚：分子动力学模拟

IF 5.2 1区化学 Q1 POLYMER SCIENCE

Macromolecules Pub Date : 2025-09-21 DOI:10.1021/acs.macromol.5c01756

Ran Chen, Chuanfu Luo, Shichun Jiang, Xiaoniu Yang

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引用次数: 0

摘要

采用粗粒度分子动力学模拟研究了等温退火过程中链端修饰对短链半晶聚合物片层增厚的影响。转变模式分析揭示了链式滑动和熔融-再结晶机制并存。片层增厚通过成核和生长两步机制进行。成核优先发生在富含非折叠链的区域，临界核大小约为30茎。在再结晶过程中，确定了两种片层生长模式：在横向生长前沿结晶和通过两个端面之一将非晶链直接插入现有片层。大链末端的引入通过在空间上阻碍展开-插入机制显著抑制了片层增厚。这些结果阐明了层状增厚的微观机制，并强调了链端尺寸在调节聚合物结晶中的关键作用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

Chain-End Modifications Suppressing Lamellar Thickening of Short Semicrystalline Polymers under Isothermal Annealing: Molecular Dynamics Simulations

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Chain-End Modifications Suppressing Lamellar Thickening of Short Semicrystalline Polymers under Isothermal Annealing: Molecular Dynamics Simulations

Coarse-grained molecular dynamics simulations are employed to investigate the effect of chain-end modifications on the lamellar thickening in short-chain semicrystalline polymers during isothermal annealing. Analysis of transformation patterns reveals the coexistence of chain-sliding and melting–recrystallization mechanisms. Lamellar thickening proceeds via a two-step mechanism of nucleation and growth. Nucleation preferentially occurs in regions enriched with nonfolded chains, with a critical nucleus size of approximately 30 stems. Two lamellar growth modes during recrystallization are identified: crystallization at the lateral growth front and direct insertion of amorphous chains into existing lamellae through one of the two end surfaces. Introduction of bulky chain ends significantly suppresses lamellar thickening by sterically hindering the unfolding-insertion mechanism. These results elucidate the microscopic mechanisms of lamellar thickening and underscore the pivotal role of chain-end size in modulating polymer crystallization.

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来源期刊

Macromolecules 工程技术-高分子科学

CiteScore

9.30

自引率

16.40%

发文量

942

审稿时长

2 months

期刊介绍： Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.