The Preparation And Application Of Carbon Dots Composites

Fluorescent carbon quantum dots which also can be called carbon dots(CDs)are a new type of carbon nanoparticles with diameters less than 10 nm.As one of the new carbon materials,CDs have attracted great interests because of their unique functions such as chemical sensing,drug delivery,photocatalyst,low toxicity and bioimaging.In this part,two new kinds of CDs composites were prepared and their applications in catalysis and optics were been studied respectively.1.A new convenient method has been developed to synthesize rhodium nanoparticles,in which carbon dots(CDs)were used both as stabilizing and reducing agents.The fluorescent CDs were prepared by microwave-assisted heating method using chitosan as raw material and the presences of hydroxyl and carbonyl on the surface of CDs were supported by FTIR spectra.Subsequently,CDs could directly reduce Rh3+ to Rh0 without additional reducing and stabilizing agents by heating Rh3+ with CDs for Ih at 120?.The resulting Rh nanoparticles have an average size of about 2.8 nm and the Rh/CDs nanoparticles also retain the fluorescent property of CDs.The hydrogenation activities of Rh/CDs nanoparticles were investigated.The results demonstrated that the nanoparticles had highly catalytic activity in the hydrogenation reaction of hydroxyl-terminated polybutadiene(HTPB)and hydroxy-terminated butadiene-acrylonitrile(HTBN).Also,the presence of CDs could improve the fluorescent properties of rubbers after hydrogenation.2.The fluorescent CDs were prepared by microwave-assisted heating method using citric acid and ethylenediamine as raw materials.Then,novel 1-methylpropargyl alcohol derivatives containing leucine side groups on their side chains were successfully synthesized and polymerized by using(nbd)Rh+[?6-C6H5B-(C6H5)3]as catalyst.Circular dichroism(CD)spectra and UV-Vis spectra revealed that the polymers took predominantly one-handed helical structures that were stable under heat.Deprotection of the t-butyloxycarboryl(Boc)groups in the homopolymers under acidic conditions produced polymers with primary amine moieties on the side chains.The polymers were soluble in water,and turbidity test revealed that the polymers were pH-responsive.The amino-acid-based polymers were further used in the enantionselective crystallization of alanine enantiomers and L-alanine was preferably induced to crystallize with the L-leucine-based polymer.Finally,a new kind of composite membrane was prepared by using CDs as fluorescent sources,helical polymers as polarizing sources,polyving akohol(PVA)as composite matrix.