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

超分子聚合物(SMPS)因其具有可逆聚合度和自愈性等特性，在材料科学领域是一个有趣而有前途的领域。目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(从而功能)的控制。本项目的目的是探索各种策略来改善基于二苯二亚胺(PDI)的超分子聚合物的控制。选择PDI作为本研究的构建块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，这使得它们成为荧光成像的有利候选者，核心之间的强相互作用以及它们作为N型半导体的特性。因此，这些因素确保了这些化合物是有希望进行研究的化合物。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化来探索对组装(由于硫化物种的空间结构的变化)和光电性质的影响(例如，导致LUMO减少和HOMO能级增加，导致更快的三重态形成导致荧光猝灭，导致吸收极大值红移)。在酰亚胺位置引入不同的基团，以增强单体之间不同的非共价相互作用，例如多重氢键、芳香族堆积和离子-离子相互作用，从而导致更快和更强的组装，或者通过引入空间位阻基团，加剧堆积。然而，亚胺取代对电子性质的影响很小，这是由于亚胺氮原子的分子轨道上的节点)。此外，海湾位置的取代导致PDI芯的平面性扭曲，导致不同的堆积行为。这种差异可以用来调节自组装，此外，对PDI的光学性质的影响比对氮亚胺的取代要大得多。预期的结果是获得关于聚合物的长度、多分散性和官能团的位置的更多自组装行为的控制，从而产生可调节和可定制的功能和特性。该项目属于EPSRC“物理科学”研究领域，更准确地说是“聚合物材料”、“合成有机材料”、“光子材料”和“能量应用材料”。

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".