Controlled Functionality and Self-Assembly of PDI-Based Supramolecular Polymers by Targeted Modification

超分子聚合物（SMPs）是材料科学中一个有趣且有前途的领域，因为它们具有吸引人的特性，包括聚合的可逆性和自愈性。当前超分子聚合领域的一个挑战是缺乏对这些动态系统的结构（以及功能）的控制。该项目的目的是探索各种策略来改善对苝二酰亚胺（PDI）基超分子聚合物的控制。选择PDI作为本研究的基石是基于它们的高稳定性（热稳定性和化学稳定性），高荧光量子产率，这使它们成为荧光成像的有利候选人，核之间的强相互作用以及它们作为N型半导体的性质。因此，这些因素确保了这些有希望被研究的化合物。提出的获得所需控制的途径是：在核心上使用不同程度的硫离子化来探索对组装（由于硫离子化物种的立体结构的变化）和光电性能的影响（例如，导致LUMO的减少和HOMO能级的增加，导致荧光被更快的三重态形成所猝灭，导致吸收最大值的红移）。在亚胺位置引入不同的基团来增强单体之间不同的非共价相互作用，如多重氢键、芳香层和离子-离子相互作用，从而使组装更快、更强，或者通过引入位阻基团来加剧堆叠。然而，亚胺取代对电子性质的影响很小，因为在亚胺氮原子的分子轨道上有节点)此外，在bay位置的取代导致PDI核心的平面度扭曲，从而导致不同的堆叠行为。这种差异可以用来调整自组装，此外，对PDI光学性质的影响比氮酰亚胺上的取代大得多。预期的结果是对聚合物的长度、多分散性和官能团位置的自组装行为进行更多的控制，从而获得可调谐和可定制的功能和特性。该项目属于EPSRC“物理科学”研究领域，更准确地说，属于“高分子材料”、“有机合成”、“光子材料”和“能源应用材料”的子组。

Supramolecular polymers (SMPs) are an interesting and promising field in material science, owing to their attractive properties, including reversible degree of polymerisation and self healability. A current challenge in the field of supramolecular polymerization is the lack of control over structure (and thus function) of these dynamic systems. The aim of this project is to explore various strategies to improve the control of perylene diimide (PDI)-based supramolecular polymers The choice of PDIs as the building blocks for this study is based on their high stability (thermal as well as chemical), high fluorescence quantum yield, which makes them favourable candidates for fluorescence imaging strong interactions between cores and their properties as N type semiconductors. These factors therefore ensure that these are promising compounds to investigate. Proposed routes to obtain the desired control are: The use of different degrees of thionation on the core to explore the influence on assembly (due to changes of the sterics of the thionated species) and optoelectronic properties (e.g., resulting in a decrease of the LUMO and increase of the HOMO energy levels, resulting in Fluorescence quenching by a faster triplet formation, resulting in a redshift of the absorption maxima). The introduction of different groups in the imide position to enhance different non covalent interactions between the monomers, e.g. multiple hydrogen bonding, aromatic stacking and ion-ion interactions, resulting in faster and stronger assembly, or by introducing sterically hindering groups, aggravating the stacking. However, the influence on the electronic properties by imide substitution is small, due to nodes in the molecular orbitals at the imide nitrogen atoms) Furthermore, substitution in bay position leads to a distortion of the planarity of the PDI core, resulting in a different stacking behaviour. This difference may be used to tune the self-assembly and, additionally, the effect on the optical properties of the PDI is much larger than substitution on the nitrogen imide.The expected outcome is to gain more control over the self-assembly behaviour regarding length, polydispersity and location of functional groups of the polymers, resulting in tuneable and customisable function and properties.This project falls within the EPSRC "Physical sciences" research area, more precisely in the subgroups "Polymer Materials", "Synthetic Organic", "Photonic Materials" and "Materials For Energy Application".