| Organic/inorganic nanocomposites have induced extensive attention and research in the fields of science and nanotechnology. The study of polymer and inorganic nanoparticles composite materials is an active field,involves chemistry, physics, biology, material science and so on. Polymer and inorganic nanoparticles composite materials are widely utilized duing to its good optical property, conductivity, electrocatalysis and biocompatible. The research of chemically modified electrode is an active field of electrochemistry and electroanalytical chemistry presently. Polymer and inorganic nanoparticles composite materials act as electrode materials have been applied to prepare biosensors, electrochromic device and so on, nanocomposite materials modified electrode has an important theorial significance and extensive application prospect in biological electroanalysis and preparation of biosensor.In this thesis, we developed our work focusing on preparation, characterization, properties of polymer and inorganic nanoparticles composite materials and its application in photocatalysis, electrocatalysis and sensor field。1. Polydopamine/Silver Conducting Nanoparticle Composite with Core-Shell Structure: Fabrication, Characterization and Application in Electrocatalysis, Photocatalysis toward Neutral RedDopamine hydrochloride (DA) (dissolved in 1.0×10-2 mol/L carbonate/bicarbonate buffer with pH 8.5) as a reductant and the source of polymer, silver nitrate ( AgNO3 ) as an oxidant and the source of silver nanoparticles (AgNPs), are mixed to yield polydopamine/silver nanoparticle composite (PDA/AgNPs) with core-shell structure. Composite material has good biocompatibility, highly uniform dispersion of the nanoparticles with a narrow size distribution, conductivity and high good catalysis and optics. It has formidable electro catalysis and photochemical catalysis to oxidize neutral red (NR).The morphology of the resulting products were characterized by scanning electron microscopy (SEM)and transmission electron microscope(TEM), we can see the particle size and core-shell construction of the PDA/AgNPs composites, the PDA film wrap the Ag nanopaticles. Moreover, optical properties were characterized using UV-Vis spectra, the characteristic peak of AgNPs was observed at 425 nm on the spectra, indicated that AgNPs was produceed. PDA film can protect AgNPs, avoiding of oxidation. photocatalysis and electrocatalysis of composite material to oxidize NR are investigated in this thesis. The resuilt demonstrated that the PDA/AgNPs expedited the degradation of NR, and the PDA/AgNPs possessed the cataytic ability to degrade the NR. Minewhile, PDA/AgNPs modified electrodes possess sensitive response to neutral red, under optimum conditions and using differential pulse mode, the reduction peak current was linearly related to the concentration of NR over the range of 1.0×10-6～1.1×10-5 mol/L with a correlation coefficient of 0.998, the detection limit was 2.1×10-7 mol/L (S/N=3). 2. Polyaniline Conducting Composite Material with Core-Shell Structure: Fabrication, Characterization and Applicationcalcium carbonate (CaCO3) microparticles act as template, adopt the technique of layer-by-layer assembly utilizing electrostatic interaction to orderly coating polyelectrolyte chitosan and sodium poly(styrene sulfonate). polyelectrolyte layers (PEs) can stabilize CaCO3 microparticles. Using CaCO3 microparticles stabilized with PEs as parent core, polyaniline (PAN) was in-situ formed around the microparticles, and formed PAN/(PEs)6/CaCO3 microparticles with core-shell structure.The morphology of the resulting products were characterized by scanning electron microscopy ( SEM ), result indicated PEs can stabilize CaCO3 microparticles, and PAN was in-situ formed around microparticles. UV-Vis spectroscopy displayed characteristic peak of PAN, demonstrated PAN layer formed.PAN/(PEs)6/CaCO3 microparticles modified electrodes possess sensitive response to DA, peak current of modified electrodes to oxidize DA is about two times than pure CaCO3 microparticles modified electrodes, demonstrated composite materials possess good conductivity.3. Polyaniline/Au Conducting Nanocomposite:Fabrication and Electrocatalysis to Dopaminepolyaniline/Au nanoparticles nanocomposite (PANI/AuNPs) was prepared via direct electroreduction of AuCl4- ions adsorbed onto glassy carbon electrode (GCE), which was previously coated with PANI via in-situ electropolymerization. The PANI/AuNPs based biosensor displayed good catalysis ability for the oxidation of dopamine (DA), and the calatytic current exhibited linear response to DA in the range of 3.0×10-6 mol/L～1.1×10-4 mol/L, with a low detection limit of 8.0×10-7 mol/L (S/N = 3).
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