Synthesis And Self-assembly Behaviour Of Amphiphilic Branched Supramoledular

Supramolecular chemistry, chemistry of the intermolecular bond, has already attracted manyresearcher workers. As the promising future of supramolecular chemistry, it has been studied in themany interdisciplinary subjects, such as chemistry, materials and biology. Supramolecular polymer isan important branch of supramolecular chemistry in the field of polymer chemistry. Due to the highlyreversible dynamic equilibrium characteristics of supramolecular polymer, it has attracted widelyattention of research workers who are interest in the field of molecular self-assembly. In various wayof constructions of supramolecular polymers, host-guest inclusion complex plays an important role inthe self-assembly of supramolecular polymer. Cyclodextrin has developed into an important moleculeof the host molecules in the supramolecular chemistry, the whole cyclodextrin molecule has a peculiarkind of cavity structure with truncated cone. Due to its unique hydrophobic internal cavity, it caninclude a variety of organic and inorganic small molecules to form hybrid complexation. In recentyears, cyclodextrin have been widely used as the driving forces to non-covalently connect hydrophilicand hydrophobic in self-assembly of supramolecular polymer.In this dissertation, based on the summarization of previous research works of supramolecularpolymer, supramolecular host-guest interaction was used to construct branched polymer. Wesynthesized different branched polymers with multiple kinds of host and guest polymers, thehost-guest complexation was utilized to couple the hydrophobic polymer with hydrophilic polymer,and then the amphiphilic branched supramolecular pseudo polymers were obtained. Subsequently, theself-assembly behaviors of them were investigated. In addition, we further explore on hyperbranchedpolymer topology structure, the hyperbranched-star-hyperbranched based on non-covalent bond weresynthesized, the self-assembly and disassembly behaviors of them in H2O were investigated. Themain results are shown as follows. 1. A POSS-Based Supramolecular Amphiphile and Its Hierarchical Self-AssemblyBehaviors：A polyhedral oligomeric silsesquioxane (POSS)-based supramolecular amphiphile is preparedfrom the host–guest inclusion complexation between a mono adamantane-functionalized POSS(AD-POSS) and a β-cyclodextrin oligomer (P(β-CD)). Assisted by the interface of H2O/toluene, theobtained supramolecular hybrids self-assemble into stable hollow nanospheres with thick walls. Thesehollow nanospheres aggregate together into a sphere layer through a spin coating technique, whichthen further transforms into a thin porous fi lm containing nanometer-scale holes. The hollownanospheres have a low cytotoxicity. The in vitro cell culture indicates the nanoporous fi lms promoteadhesion and proliferation of cells. The self-assembly morphologies and structures have beencarefully characterized by SEM, TEM, AFM, DLS, XPS and watercontact angle measurements, andthe self-assembly mechanism has also been discussed.2. Synthesis and its photo-responsive self-assembly behavior of start-like amphiphilichyperbranched-star-hyperbranched supramolecular pseudo polymer.HBPO-star-PEO-Azo was synthesized according to the acyl chlorination reaction between4-(phenyldiazenyl) benzoic acid and the amphiphilic hyperbranched multiarm copolymer ofHBPO-star-PEO, where HBPO represents the hydrophobic hyperbranched poly(3-ethyl-3-oxetanemethanol) core and PEO represents the hydrophilic poly(ethylene oxide) arms. andhydrophilic hyperbranched polyglycidol with cyclodextrin as core (β-CD-g-HPG) were synthesizedaccording to the oxyanionic ring-opening multibranching polymerization. The recognization ofcyclodextrin and azobenzene was achieved by adding selected solvent to common solvent, and then,star-like amphiphilic hyperbranched-star-hyperbranched supramolecular pseudo polymer wasobtained. After dialysis against water, the self-assembly of supramolecular polymer was completed.DLS and2D NOESY were used to track the formation and self-assembly process of star-likesupramolecular polymer, the results demonstrated the complexation of cyclodextrin and azobenzene.TEM and SEM were used to directly detect the morphology of the self-assembly objects. The resultsindicated that the supramolecular polymer self-assembled into vesicle in water, and the thickness ofthe vesicle wall was about20nm. The vesicles may possess a bilayer structure with two β-CD-g-HPGshell layers and HBPO-star-PEO-Azo core layer. And UV light with365nm was used to investigatethe stability and the disassembly behaviour of supramolecular vesicles. The results show that thesupramolecular viescle was stable with competitive host or guest moleculars, disassembled withirradiation of UV light with365nm.