Construction And Properties Of Hierarchical Supramolecular Polymerization System

Self-assembly is common in nature and it is one of the most sophisticated approaches used by living organisms to construct desirable architectures using molecular building blocks.Inspired by nature,the construction of non-covalent bond driven functional artificial self-assembly system has become an interdisciplinary research hotspot.So far,great research work has been carried out on the primary level self-assembly of monomers to supramolecular polymers,and the relationship between assemblies and properties has been established.In recent years,our research group has built a supramolecular polymer system with a biomimetic "nucleation-elongation growth" mechanism.As a consequence,the improvement of polymerization controllability and structure order can be improved.Considering that the precision and complexity of biological structures are based on hierarchical self-assembly structures,this dissertation focuses on the development of hierarchical supramolecular polymerization system.On this basis,the influence of molecular structure parameters on hierarchical assembly and properties was explored,and the functional applications of hierarchical supramolecular polymers were expanded.(1)In the first part of the work,before the construction of hierarchical supramolecular polymerization systems,we used organometallic complexes as the building block and one-dimensional supramolecular polymers have been successfully obtained via the non-covalent interactions.We further explored the polymerization mechanism of supramolecular polymers.Compared with organoplatinum(Ⅱ)-based supramolecular monomers,organogold(Ⅰ)complexes showed stronger supramolecular polymerization ability and higher anti-disassembly ability.In addition,the application of organometallic supramolecular polymers in light-harvesting systems has been expanded.(2)By exploring the self-assembly mechanism of one-dimensional supramolecular polymers,we expect to further construct more complex hierarchical self-assembly structures.In the second part,we established a microemulsification method based on covalent polymer.Supramolecular polymer nanoparticles were obtained with the assitant of surfactant,and we demonstrated that the method is suitable for different systems.The resulting nanoparticles exhibited the similar spectral properties as one-dimensional supramolecular polymers.At the same time,the compartmentalization of nanoparticles prevented the quenching effect of oxygen on phosphorescence.(3)In the third part of the work,we employed platinum(Ⅱ)acetylide complexes as the luminescent unit.Through the introduction of supramolecular chiral signal,we obtained the circularly polarized luminous monomers.Supramolecular polymer nanoparticles were prepared by the above microemulsification method.On this basis,a receptor with similar structure was co-assembled together to realize the simultaneous transfer of luminescence and chirality in the excited state.(4)In the three parts of the work mentioned above,we first explored the assembly mechanism of one-dimensional supramolecular polymer and prepared it into multilevel subsupramolecular polymer nanoparticles by microemulsification method.In addition,we know that liquid crystal is another common hierarchical supramolecular polymer structure.Hence,in the last part,we constructed supramolecular polymers driven by hydrogen bonds.The different structures formed at different concentration scales were also studied.In dilute solution,the monomers were driven by hydrogen bonds to form a one-dimensional supramolecular polymer.With further increase of concentration,the supramolecular polymer can form a hierarchical structure of lyotropic liquid crystals in situ.With further increase of concentration to solid,thermotropic liquid crystals phase can be formed.Finally,the influence of peripheral alkyl chain branching on the supramolecular structure at different levels was also investigated.