Study On The Functionalization Of Graphene And Its Applications

Graphene has attracted great attentions, due to its intrinsic2-D structures, outstanding physical and chemical properties as well as their promising potential applications in the areas of material science, electronic science, biomedicine and catalyst carrier etc. However, graphenes cannot be dispersed in most of solvents and other materials because of the strong Van der Waals force interactions, which greatly hampers their research and potential utilities. It is of great significance to functionalize graphene in order to improve its dispersibility in solvents and matrics. Up to date, various functionalization methods have been reported, including noncovalent and covalent functionalization. The covalent functionalization can not only improve the solubility of graphene, but also afford it with novel properties and enlarge its application scope. In this dissertation, linar polymers covalently functionalized graphenes have been prepared by atom transfer nitroxide radical coupling reaction (ATNRC) and single-electron transfer living radical polymerization (SET-LRP). Utilizing the polymer functionalized graphenes as carriers, trypsin has been successfully immobilized onto graphenes. A new method of microwave-assisted on-plate proteolysis has been advanced, and applied on the quick proteolysis of trace of protein. The main research contents and results are shown as follow:1. HTEMPO active groups could be introduced to the surface of graphene oxide via an esterification reaction, and graphene oxide was simultaneously reduced. Then, The atom transfer nitrogen oxygen free radical coupling reaction (ATNRC) with Br terminated polymers was conducted to obtain polymer covalently functionalized graphene. This method extends the range of graft-onto stragety for covalent modification of graphene. Br terminated polymers prepared via ATRP could be covalently grafted onto the surface of graphene. Polystyrene colvalently functionalized graphene (Graphene-g-PS) has been prepared by this method. Due to the covalent grafting of polystyrene, Graphene-g-PS could be well dispersed in chloroform, methanol, hexane, toluene, and other organic solvents, which is favorable to the further applications of graphene.2. Polymer covalently functionalized graphene has been prepared by graft-from strategy. Firstly, through the azido reaction, SET-LRP initiator was covalently grafted on the surface of graphene to initiate the polymerization of tBMA, so as to obtain polymer covalently grafted graphene (G-PtBMA). The graft ratio of PtBMA could be controlled by controlling the concentration of azide salt. The Raman,1H NMR, TEM, AFM, and TGA characterization indicated that PtBMA chains have been covalently grafted onto the surface of graphene. As a result of PtBMA covalent functionalization, G-PtBMA showed good dispersibility in polar solvent, which is favorable to the subsequent applications of graphene.3. Polylysine (PCL) and polyethylene glycol (PEG) were covalently graft onto the surface of graphene oxide, followed by immobilizing trypsin, enzyme immobilized probe was obtained. Its application on microwave assisted hydrolysis of bovine serum protein and myoglobin was studied. The MALDI-MS results showed that enzyme immobilized graphene probe could enhance the efficiency of protein hydrolysis, and decrease the hydrolytic reaction time, which is favorable to the rapid and efficient identification of protein.