Studieson Supramolecular Polymer And Graphene Functionalization Basedon "Click" Chemistry

The "click"reactions have attracted tremendous attention for their robust and efficient characteristics since Prof. Sharpless put forward the concept of "click" chemistry in2001. Combining the research focus, we reserched a multi-responsive self-healing metallosupramolecular material based on CuAAC "click" ligand and modified the chemically reduced graphene via Diels-Alder "click" reaction.The tridentate ligand2,6-bis(1-propan-l-ol-1,2,3-triazol-4-yl)pyridine (BTP) was firstly synthesized by CuAAC "click" chemistry. Then,we conducted UV-Vis titrations experiments to make sure the coordination relationship between BTP and metel ions(Zn(Ⅱ)、Eu(Ⅲ)), the results showed that coordination led to stable1:2complexes in the case of Zn(Ⅱ) and1:3complexes in the case of Eu(Ⅲ).We also researched the photoluminescence spectra of the metal:BTP complexes, the intensity of the BTP ligand increased after complexed with Zn(Ⅱ) and appeared"antenna effect" based on Eu(Ⅲ). Various solvents showed coordinated competition effect with metal-ligand complexes, which provided theoretical foundation for the metallosupramolecular research based on BTP.Then,the metal ligand BTP was introduced into the polymer backbone via polyurethane reaction.The metallosupramolecular gel were constructed by adding Zn(Ⅱ) and Eu(Ⅲ) and swelled using inert solvents such as chloroform,1,1,2,2-tetrachloroethane toluene and so on. The metallosupramolecular gel had high swelling ratio, excellent mechanical properties, interesting optical properties and showed thermo-, photo-, and chemo-responsive which are tunable by careful selection of metal ions and their combinations, swelling solvent, concentration, and so on. At the same time,the material could be effectively self-repaired many times even at the same site,which could be used as a self-healing metal coating.Cyclopentadienyl functionality was efficiently introduced to poly(ethylene glycol) monomethyl ether by two step nucleophilic substitution. Then,the mPEG-Cp was grafted onto chemically reduced graphene using Diels-Alder [4+2] cycloaddition at80℃as well as at ambient temperature without any catalysts. Various spectroscopic tools (Raman, FTIR, XPS), XRD, TGA and nanoscopic scale observations (AFM, SEM, HRTEM) were used to provide evidence for the successful DA "click" functionalization. The thermogravimetric analysis (TGA) revealed that the grafting ratios at ambient temperature and at80℃were16.7%and21.8%, respectively. And the functionalized graphene dispersed well in water as well as many organic solvents. The one-step Diels-Alder [4+2]"click" reaction thus creates a facile and innovative strategy for graphene functionalization, which may widen the application scope of the material.