Dynamics and Structural Evolution in Supramolecular Polymer Networks

本项目旨在系统地研究超分子聚合物网络中的链和连接动力学；它还旨在评价这种动力学如何在它们的纳米结构演化中表现出来。这将为模拟和预测超分子聚合物支架的自愈动力学提供一个基本的理解。为了实现这一目标，我们建议引入一类新的超分子聚合物网络，形成一个模块化的工具箱。我们将使用单分散、线形和星形的聚乙二醇前驱体，并为它们配备互补基序，这些基序通过多个氢键或通过强度明显不同的过渡金属络合形成超分子缔合。为了探索这些不同超分子聚合物网络的纳米尺度结构及其时间演化，我们建议应用光散射(LS)、小角中子散射(SANS)和小角X射线散射(SAXS)；这将在微流控通道中的宏观样品和微米尺度样品中完成。此外，我们将研究通过凝胶扩散的荧光标记示踪链的动力学；这将通过光漂白后荧光恢复(FRAP)来完成。针对超分子聚合物网络动力学的不同理论模型，包括Cates模型和Rubinstein-Semenov模型，对结果进行了讨论。这项工作的目标是评估这些理论的实用性，以进一步模拟超分子聚合物凝胶的自我愈合。

This project aims to systematically study chain and junction dynamics in supramolecular polymer networks; it also aims to appraise how this manifests itself in their nanostructural evolution. This will yield a fundamental understanding to model and predict the dynamics of self-healing of supramolecular polymer scaffolds. To achieve this goal, we propose to introduce a new class of supramolecular polymer networks that forms a modular toolbox. We will use monodisperse linear and star-shaped polyethylene glycol precursors and equip them with complementary motifs that form supramolecular associates via multiple hydrogen bonding or via transition metal complexation with markedly varying strength. To probe the nanometer-scale structure of these different supramolecular polymer networks, along with its temporal evolution, we propose to apply light scattering (LS), small-angle neutron scattering (SANS), and small-angle x-ray scattering (SAXS); this will be done both with macroscopic samples and with micrometer-scale samples in microfluidic channels. In addition, we will investigate the dynamics of fluorescently labeled tracer chains that diffuse through the gels; this will be done by fluorescence recovery after photobleaching (FRAP). The results will be discussed in view of different theoretical models on supramolecular polymer network dynamics, including the Cates and the Rubinstein-Semenov models. The goal of this effort is to evaluate the utility of these theories for further modeling of the self-healing of supramolecular polymer gels.