Study On Novel Preparation Technology Of Dissolved Oxygen Sensing Film Based On Fluorescence Quenching

The measurement of dissolved oxygen(DO) concentration is important in various areas of environmental monitoring, industry, clinical and aquaculture. Traditionally, DO is measured based on the Clark electrode(CE). However, the CE method is easily poisoned by sample constituents(e.g.H2 S, proteins), and it will destroy the analyte by consuming oxygen during measurement. Therefore, the researches of optical dissolved oxygen sensors based on the quenching of fluorescence have gotten attention of people in recent years, which have a fast response time, high sensitivity and can achieve measurement on line. Dissolved oxygen sensing film is an important component of optical dissolved oxygen sensor, which consists of oxygen-responsive luminophore and supporting matrix. With the development of industry, it is necessary to improve the sensitivity, long-term stability and other properties of sensing film presently. This thesis adopts fluoride modified sol-gel method and polymeric nanoparticles to prepare sensing film with high-performance.3,3,3-trifluoropropyltrimethoxysilane( TFP-TMOS) and tetraeth-oxysilane(TEOS) are used as precursors, Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium( Ⅱ) dichloride is used as oxygenresponsive indicator, dissolved oxygen sensing film is fabricated via sol-gel process. By single factor experiments, the process parameters of sol-gel method is optimized. The surface morphology and sensing property of the optimized sensing film are studied. And the property of film like response time, sensitivity were also made. The results show that the dissolved oxygen sensing film based on fluorinated sol-gel method is characterized of high sensitivity,fast response, good long-term stability.The amphiphilic RAFT(amphi-RAFT) agents are used both as a surfactant and RAFT agent, methyl methacrylate(MMA) is used as monomer, azodiisobutyronitrile(AIBN) is used as initiator, paraffin(the melting point: 25 ℃) and Tris(4,7-diphenyl-1,10- phenanthroline)ruthenium( Ⅱ) dichloride is used as the core material, the indicator contained polymeric nanoparticles were synthesized by the interfacially confined RAFT miniemulsion polymerization. The influence of the amount of AIBN on the morphology of the indicator contained polymeric nanoparticles and convert ratio of monomer were investigated, the law of the amount of a mphi-RAFT agent on the size of nanoparticles is studied.The results show that indicator is successfully immobilized into polymeric nanoparticles, and the size of spherical nanoparticles is uniform. The sizeof nanoparticle is decreased with larger amout of mphi-RAFT used.Meanwhile, the indicator contained polymeric nanoparticles is dispersed into the optimized fluoride modified sol-gel matrix to prepare sensing film with higher performance.