Free Energy Trajectory for Escape of a Single Chain from a Diblock Copolymer Micelle
Free Energy Trajectory for Escape of a Single Chain from a Diblock Copolymer Micelle
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单链从二嵌段共聚物胶束逃逸的自由能轨迹
DOI：
10.1021/acsmacrolett.1c00508
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发表时间：
2021
影响因子：
7.015
通讯作者：
Lodge, Timothy P.
中科院分区：
文献类型：
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作者：
Seeger, Sarah C.;Dorfman, Kevin D.;Lodge, Timothy P.
我们使用伞采样计算的自由能轨迹的单链进行驱逐从一个孤立的二嵌段共聚物胶束。这种方法阐明了实验上不可观察的过渡态，确定了最大自由能的空间位置，并揭示了单链的链构象，因为它经历驱逐。结合伞形采样和耗散粒子动力学模拟的A4 B8胶束揭示了被驱逐的链的核心块（A）保持部分拉伸的过渡状态，在一些先前的模型中假设的塌陷状态相反。自由能垒随着Flory-Huggins相互作用参数χ线性增加，直到大的相互作用能，其中另外的球形核的结构在过渡态附近明显变形。
We use umbrella sampling to compute the free energy trajectory of a single chain undergoing expulsion from an isolated diblock copolymer micelle. This approach elucidates the experimentally unobservable transition state, identifies the spatial position of the maximum free energy, and reveals the chain conformation of a single chain as it undergoes expulsion. Combining umbrella sampling with dissipative particle dynamics simulations of A4B8micelles reveals that the core block (A) of the expelled chain remains partially stretched at the transition state, in contrast with the collapsed state assumed in some previous models. The free energy barrier increases linearly with the Flory–Huggins interaction parameter χ up to large interaction energies, where the structure of the otherwise spherical core apparently deforms near the transition state.