A Variational Field-Theoretical Approach to Control the Center-Of-Mass of Macromolecules

IF 5.1 1区化学 Q1 POLYMER SCIENCE

Macromolecules Pub Date : 2024-11-07 DOI:10.1021/acs.macromol.4c01494

Luofu Liu, Chao Duan, Rui Wang

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Abstract

Trapping macromolecules is important for the study of their conformations, interactions, dynamics, and kinetic processes. Here, we develop a new theory using a Gaussian variational approach to confine the center-of-mass of polymers. It self-consistently introduces a mean force that controls the average position of the center-of-mass and a self-adjustable harmonic potential that counters the fluctuation of the center-of-mass position. The effectiveness and versatility of our theory are verified in three classical yet not fully understood problems in polymer science: (1) single-chain conformation in the whole regime of solvent quality, (2) globule-pearl necklace-coil transition of a polyelectrolyte, and (3) interchain interaction by simultaneously confining two polymers. The scaling relationships and θ behaviors are well captured. Conformations with large shape anisotropies appearing in charged polymers are clearly depicted. Being a field theoretical framework, our theory also facilitates visualization of the conformational response and kinetic process. Our theoretical prediction of the radius of gyration of poly(N-isopropylacrylamide) (PNIPAM) is in quantitative agreement with experimental results reported in the literature.

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控制大分子质量中心的变分场理论方法

捕获大分子对于研究其构象、相互作用、动力学和动力学过程非常重要。在此，我们利用高斯变分法开发了一种新理论，用于限制聚合物的质量中心。它自洽地引入了一个控制质量中心平均位置的平均力和一个可自我调节的谐波势，以抵消质量中心位置的波动。我们的理论的有效性和多功能性在聚合物科学中三个经典但尚未完全理解的问题中得到了验证：(1) 在整个溶剂质量体系中的单链构象；(2) 聚电解质的球珠项链盘旋转变；(3) 同时限制两种聚合物的链间相互作用。模型很好地捕捉到了缩放关系和 θ 行为。带电聚合物中出现的具有较大形状各向异性的构象被清晰地描绘出来。作为一种场理论框架，我们的理论还有助于构象响应和动力学过程的可视化。我们对聚（N-异丙基丙烯酰胺）（PNIPAM）回旋半径的理论预测与文献报道的实验结果在数量上是一致的。

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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.