Surface Decoration Of Carbon Black/Cnts By Dopamine

Dopamine （3,4-dihydroxyphenethylamine） was one kind ofneurotransmitter in living organism and this compound has excellentattachment to almost all wet substrates （including metals, ceramics,semiconductors, and polymers） for the the oxidative polymerization ofdopamine under aerobic and alkaline condition. The abundant catechol andamine in polydopamine （PDA） constructs a platform for further modificationof a substantial number of substrates. In our work, dopamine was used toprepare hydrophilic carbon black （CB） and Fe₃O₄-deposited magnetic carbonnanotubes （CNTs）. The contents are as follows:（1） Hydrophilic carbon black was prepared by the deposition ofpolydopamine （PDA） which polymerized through the oxidation of dopamineunder aerobic and alkaline condition. The polymeric condition and mechanismwere also studied. Finally, the products were characterized by X-rayphotoelectron spectroscopy （XPS）, Fourier transform infrared spectroscopy（FTIR）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, static contact angle measurements, natural placementmeasurements, particle size distribution measurements and thermalgravimetric analysis （TGA）. All the results show that PDA deposited on thesurface of CB successfully, and CB changed from hydrophobic to highlyhydrophilic and kept excellent heat-resistance;（2） Magnetic CNTs composite was prepared. PDA ad-layer encapsulatedon the surface of CNTs first, then Fe³⁺was adsorbed by PDA and settled toform Fe₂O₃. Finally, Fe³⁺and Fe²⁺were adsorbed by PDA again, Fe₂O₃wasused as seed to induce the coprecipitation of Fe₃O₄under strong alkalinecondition. The products were characterized by TEM, X-ray diffraction （XRD）,FTIR, Raman spectra, XPS and vibrating sample magnetometer （VSM）. Theresults confirm that Fe₃O₄nanoparticles deposited on the surface of CNTsuniformly, and the final product was soft magnetic and composed of CNTs、PDA、Fe2O3and Fe₃O₄.