标题： 动态键对超分子二嵌段共聚物无序-有序转变动力学路径的影响 显示英文标题

标题： Effects of Dynamic Bonds on the Kinetic Pathways of Supramolecular Diblock Copolymers Disorder-Order Transition

摘要： 超分子嵌段共聚物（SBC）由通过超分子键连接成定义明确的结构的共价聚合物构建块组成。 在动态和可逆的超分子相互作用的帮助下，预计SBC自组装可能表现出比其共价类似物更多样化的形态和刺激响应性。 在基本层面上，这些特性与自组装的自由能景观有关。 因此，理解动态/可逆键在结构转变过程中对自由能景观的影响至关重要。 在本研究中，我们首先进行智能蒙特卡洛模拟，比较超分子二嵌段共聚物（SDBC）与共价二嵌段共聚物（CDBC）的无序-有序转变（DOT）的动力学。 CDBC的结构有序参数在不同的随机数种子和初始构型下表现出快速而平滑的转变过程。 相反，SDBC系统显示出更多样的转变路径，可分为三种类型。 这些结果表明，可逆的超分子相互作用使路径复杂化，并带来了各种中间结构。 接下来，我们应用字符串方法构建转变的最小自由能路径，从中评估转变态和自由能垒。 发现转变自由能垒与超分子的比例强烈相关。 通过将自由能分解为A-B相互作用能和结合能，我们发现这两种效应的相互作用决定了动力学路径和最终的平衡结构。 显示英文摘要

摘要： Supramolecular block copolymers (SBC) consist of covalent polymer building blocks that are connected into well-defined architectures via supramolecular bonds. Assisted by the dynamic and reversible supramolecular interactions, it is envisaged that SBC self-assemblies may exhibit more diverse morphologies, stimuli-responsivity comparing to their covalent analogues. At the fundamental level, these features are related to the free-energy landscape of self-assemblies. It is therefore of central importance to understand the impact of dynamic/reversible bonds on the free energy landscape during structure transitions. In this study, we first conduct smart Monte Carlo simulations to compare the kinetics of the disorder-order transition (DOT) of supramolecular diblock copolymers (SDBC) to that of covalent diblock copolymers (CDBC). The structural order parameter for CDBC exhibits a fast and smooth transition process across different random number seeds and initial configurations. In contrast, the SDBC system shows more diverse transition pathways, which can be classified into three types. These results suggest that reversible supramolecular interactions complicate the pathways, and bring about various intermediate structures. Next, we apply the string method to construct the minimum free energy path of the transition, from which the transition state and the free energy barrier are evaluated. It is found that the transition free energy barrier strongly correlates with the fraction of supramolecules. By decomposing the free energy into A-B interaction energy and association energy, we found that the interplay of both two effects decide the kinetic pathway and the final equilibrium structures.