Synthesis And Application Of PPV@MSN Functionalized Graphene Oxide Fluorescent Hybrid Materials

Graphene oxide has a large amount of functional groups which are modified byvarious substances. Graphene oxide also has good solubility in water, the uniqueoptical and thermal properties and so on. Therefore, it has been widely applied inmany fields. Fluorescent sensors are becoming more and more important in detectiondue to their easy use, low cost, high efficiency and good selectivity. Based on thedetection of mercury ions and explosives, fluorescent sensors have been applied inmany fields, such as environmental and biological applications. The novel fluorescentchemical sensor was designed and synthesized based on graphene oxide andfluorescent nanoparticles, to detect explosives TNT and mercury ion in aqueoussolution through fluorescence resonance energy transfer (FRET). Herein, the thesisincludes two parts:The first part reported a convenient method to prepare water-soluble grapheneoxide (GO) functionalized by amine-modified mesoporous silica nanoparticles (MSNs)containing poly(p-phenylenevinylene) via covalent bonds. The resultedGO-PPV@MSN hybrid materials had a good dispersion and strong greenfluorescence in aqueous solution. The structure, morphology and optical properties ofthe resulting hybrid materials were characterized. The GO-PPV@MSN can be used asa novel and effective fluorescent sensing platform for detection of2,4,6-trinitrotoluene (TNT) in aqueous solution by fluorescence resonance energytransfer (FRET). Upon the addition of TNT, the amino groups on the surface ofPPV@MSN can bind TNT molecules from solution by forming Meisenheimercomplex, and this complex can absorb the green part of visible light, and stronglysuppress the fluorescence emission of GO-PPV@MSN through FRET. The observedlinear fluorescence intensity change allowed the quantitative detection of TNT with adetection limit down to1.310-7M.In the section, the lactam rhodamine6G (SRh6G) was introduced into aminationof mesoporous silica nanoparticles (PPV@MSN-NH2) channel by physical adsorption.Then the mesoporous silica nanoparticles were covalently grafted to the surface ofgraphene oxide. The GO-PPV@MSN-NH2@SRh6G hybrid materials had stronggreen fluorescence and a good dispersion in aqueous solution. The hybrid materials can be used as fluorescent ratiometric probe detection of Hg2+in aqueous solutionthrough FRET. The observed linear fluorescence intensity change could allow thequantitative detection of TNT with a detection limit of7.1×10-8M in water.