Controllable Self-assembly Research Of Supramolecular Polymers Cross-linked By Metallacycles

Supramolecular chemistry refers to the science of studying the special chemical properties of molecules based on non-covalent bond interactions.Supramolecular polymers,an important research field of supramolecular chemistry,refer to polymer arrays with polymer properties in solution or solid state formed by self-assembly of highly oriented and intermolecular reversible non-covalent interactions.Self-assembly is widespread in nature,and self-assembly of supramolecular polymers has attracted interest because of its special structure and function.The self-assembly of aspheric polymer nanoparticles has received extensive attention due to its special function.However,constructing aspheric polymer nanoparticles with controllable shape and size remains a significant challenge.Based on the hierarchical self-assembly works that our research group has studied,this thesis will use metal-organic macrocycles formed by coordination-bonded driven self-assembly as the core to extend the traditional high molecular polymer to synthesize heteroarmed star-shaped supramolecular polymer,and the properties of the formed polymers will be studied.This thesis is divided into the following sections:Chapter one,the research progress of supramolecular polymers is briefly introduced.The construction of supramolecular polymers,the construction of starshaped supramolecular polymers,supramolecular polymers based on metal organic macrocycles and the self-assembly of supramolecular polymers are reviewed respectively.The research topic of this thesis will be put forward at the end.Chater two,a chiral metal organic macrocyclic supramolecular polymer based on a post-modification strategy will be designed and synthesized.The supramolecular polymer could be dissolved in water to construct a multi-stimulus hydrogel.According to the temperature dependence property of polyisopropylacrylamide(PNIPAM)chain,the low critical solution temperature and the temperature response of the gel formed by the polymer will be studied.Due to the dynamic reversibility of the metal organic macrocycle,the hydrogel exhibits good self-healing properties.Further,based on the chiral characteristics of the macrocycle,PNIPAM with different chain lengths will be synthesized to control the overall chirality of the polymer.Chapter three,combination of crystalline poly(ε-caprolactone)(PCL)and an immiscible component poly(N-isopropylacrylamide)(PNIPAM)within a rigid macrocyclic junction allowed for the construction of a new metallacycle-linked heteroarms star polymers(HASPs),from which the large-area and regular cubic particles were obtained through crystallization-driven self-assembly.By varying the PCL chain length,temperature and solvent,the well-controlled formation of cubic particles has been successfully realized.Moreover,the possible formation mechanisms of such polymeric nanocubes have been explored by using dissipative particle dynamics simulations.Chapter four,based on the research of the third chapter,a heteroarm star-shaped polymer with a metal macrocycle as a crosslinking point will be constructed.A rigid metal-organic macrocycle will be ueed as a core,which orthogonally connected crystalline polymer polycaprolactone(PCL)and mutually incompatible methacrylic acid N,N-dimethylaminoethyl ester(PDMAEMA).The polymer can also be crystallized to drive self-assembly to form cubic configuration nanoparticles.Because of the acid-base responsiveness property of PDMAEMA,which is different from the PNIPAM segment,the effect of pH on the crystallization-driven self-assembly process will be further investigated.