Synthesis And Functionalization Of Fluorescence Carbon Nanoparticles

Fluorescent carbon nanoparticles (CNPs), which are discrete quasi-sphericalnanoparticles with sizes less than10nm and excitation wavelength dependentphotoluminescence behavior, have attracted much attention in recent years. In thisthesis, CNPs were synthesized through the hydrothermal carbonization ofethylenediaminetetraacetic acid disodium salt (EDTA·2Na)， which can emitblue-green light. Subsequently, photoisomeric spiropyran and polysthrene brush werefunctionalize on CNPs surface to optimize the material properties of CNPs forwidening its applications in energy conversion/storage, engineering technology. Themain contents and the results of this work are as following:1. In this thesis, we synthesize blue-green fluorescent carbon nanoparticles by thehydrothermal carbonization of EDTA·2Na. The fluorescent CNPs are almostmonodispersed and have diameters of about3nm. The surface of the CNPs has theoxygen functional groups, such as carboxylic, hydroxyl groups.2. Spiropyran-functionalized CNPs exhibiting reversible fuorescence modulationbetween blue-green and red fuorescence emission have been obtained by modifyingcarboxyl spiropyran onto the surface of CNPs. The reversible modulation of thespiropyran-functionalized CNPs is due to the fluorescence resonance energy transfer(FRET) from the CNPs to the open-ring state MC and the transformation ofspiropyran moiety structures upon UV and visible light irradiation. Thespiropyran-functionalized CNPs not only show good photo-reversibility but alsopossess high stability and relatively fast photoresponsivity.3. CNPs were grafted with polystyrene using a “grafting from” method via atomtransfer radical polymerization (ATRP). The fluorescent carbon nanoparticles graftedwith polystyrene (f-CNP-g-PS) were characterized using nuclear magnetic resonance,Fourier transform infrared spectroscopy, transmission electron microscopy,gelpermeation chromatography, dynamic light scattering and fluorescencespectroscopy. The synthesized f-CNP-g-PS are fluorescent in solution or in the solidstate with the appropriate excitation wavelength and exhibit better dispersibility andprocessability compared to CNPs.4. Styrene and acrylic acid were polymerized on the surface of carbon nanoparticles,modified with an S-1-Dodecyl-S’-(α,α’-dimethyl-α’’-acetic acid) trithiocarbonate layer (DATC), via surface-initiated reversible addition-fragmentation chain transfer(RAFT) polymerization. The fluorescent carbon nanoparticles grafted with PS-b-PAA(f-CNP-g-PS-b-PAA) were characterized using nuclear magnetic resonance, Fouriertransform infrared spectroscopy, gelpermeation chromatography, and fluorescencespectroscopy. The molecular weight of the carbon nanoparticles coated withpoly(styrene-b-acrylic acid) can be easily manipulated by adjusting the molar ratio ofmonomer/CNPs and the polymerization time.