发表机构
Kyungpook National University（庆北国立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文构建二维两态修正蠕虫状链模型，研究具有可逆自发曲率的半柔性聚合物弹性，发现拉伸或弯曲会诱导弹性转变，两种系综弹性响应存在差异，弯曲态刚度更高时拉伸或出现重入转变。
AI 中文摘要
许多半柔性丝状体呈现结构不对称性，导致其存在弯曲基态（即无热涨落、外力或力矩时的曲率），该性质被称为自发曲率。许多半柔性聚合物可通过内部构象转变或与分子环境的瞬时相互作用，可逆地产生自发曲率。本文表明，即使弯曲刚度值无变化，这种可逆自发曲率也为系综依赖的弹性提供了一种极简机制。我们在二维中构建了解析可处理的两态修正蠕虫状链模型，其中无曲率态（无自发曲率）与弯曲态（具有自发曲率）竞争，转变由激活能控制。在弱弯曲近似下，我们得到了受拉伸丝状体的吉布斯和亥姆霍兹配分函数，该丝状体具有可逆的恒定（沿主链均匀）或正弦自发曲率；还得到了受端力矩或弯曲力驱动的接枝双稳态丝状体的配分函数。拉伸或弯曲会诱导从自发曲率主导的弹性向熵弹性的转变，我们展示了两种系综（吉布斯系综 vs 亥姆霍兹系综）中弹性响应的差异。此外，我们还考虑弯曲态的弯曲刚度值更高的情况，此时拉伸双稳态丝状体时可能出现重入转变。
英文摘要
Many semiflexible filaments exhibit structural asymmetries that lead to a curved ground state (curvature in the absence of thermal fluctuations, external forces, or torques). This property is known as spontaneous curvature. Many semiflexible polymers can reversibly develop spontaneous curvature through internal conformational transitions or through transient interactions with their molecular environment. In this article, we show that such reversible spontaneous curvature, even in the absence of transitions in the value of the bending stiffness, provides a minimal mechanism for ensemble-dependent elasticity. We formulate an analytically tractable two-state modified wormlike-chain model in two dimensions, in which an uncurved state (without spontaneous curvature) competes with a curved state (possessing spontaneous curvature). The transition is controlled by an activation energy. Within the weak-bending approximation, we obtain the Gibbs and Helmholtz partition functions for a stretched filament with reversible constant (uniform along the backbone) or sinusoidal spontaneous curvature and for a grafted bistable filament driven either by an end torque or a bending force. Stretching or bending induces a crossover from spontaneous-curvature-dominated to entropic elasticity. We show how the elastic response differs in the two ensembles (Gibbs vs Helmholtz). In addition, we consider the case where the curved state is also characterized by a higher value of the bending stiffness. In that case, a reentrant transition is possible as we stretch the bistable filament.
Comments19 pages, 20 figures
Journal refJ. Chem. Phys. 165, 064111 (2026)
