Design And Synthesis Of Smart Multi-walled Carbon Nanotube Based On Carbon Dots

Smart carbon nanotubes(CNTs)was widely used in various fields of electrochemistry and construction of functionalized nanomaterials with thermal responsiveness.They are of great significance in the preparation of structures,solar cells,fuel cells,supercapacitors and drug delivery.However,the lack of reaction sites between nonpolar CNTs and polar smart polymers greatly hampers the fabrication of smart CNTs.Moreover,the conventional binding method between nonpolar CNTs and polar smart polymers was complex and destructive.For instance,the conventional methods usually utilize strong oxidants(such as concentrated nitric acid,concentrated sulfuric acid)to treat the CNTs.As a result,the treated CNTs could behave a surface with carboxyl or hydroxyl groups or introduce reaction sites.This method causes the surface structure and properties of CNTs to be destroyed and not universal,which affects the potential application properties of smart CNTs.Therefore,it was of certain significance to find a suitable and universal undamaged modification method toward the construction of smart CNTs.Carbon dots,also known as carbon quantum dots,are water-soluble and fluorescent as a typical water-soluble fluorescent nanomaterials.These two properties come from two properties of carbon dots,water solubility comes from polar functional groups and fluorescence characteristics come from its non-polar functional groups.That is to say,carbon dots had both polar structure and nonpolar structure of carbon materials,thus making the modification of carbon nanotubes to be possible.Because of the high damage structure around the carbon dots,it can be used to introduce oxygencontaining functional groups for non-destructive modification,so that CNTs can change from hydrophobic to hydrophilic.So,carbon dots can be used as natural linkers to construct a simple and general method to enable the integration of nonpolar 1-dimensional carbon nanotubes and polar smart polymers together without any damage.For the first time,the smart carbon materials with ‘ON-OFF' effect with nondestructive modification was fabricated.Based on the above mentioned,this thesis carries out the following two parts of work: 1.In this experiment,a general non-destructive modification method for intelligent multi-walled carbon nanotubes was established.First,the carbon dots are connected to the multi-walled carbon nanotubes(MWCNTs)by ?-? action,endowing multi-walled carbon nanotubes with water solubility.Then,based on the reaction between the modified multi-walled carbon nanotubes and initiator of AIBA,the initiator valence bond immobilized on the modified carbon point on multi-walled carbon nanotubes,resulting in the MWCNTs transformed to a polymerizable substrate.The smart polymer thus could be in situ grown onto MWCNTs via the following atomic radical polymerization reaction.2.A thermoresponsive polyisopropylacrylamide and pH responsive polyacrylic acid were modified onto the surface of MWCNTs using the above mentioned method.Thermosensitive nanocomposites multi-walled carbon nanotubes-carbon dotspolyisopropylacrylamide(MWCNTs-CDs-PNIPAm)and pH responsive nanocomposites multi-walled carbon nanotubes-carbon dots-polyacrylic acid(MWCNTs-CDs-PAA)were prepared.Their structural and surface properties of the two functionalized MWCNTs were characterized respectively.Based on this,their electrochemical intelligence responsiveness was further investigated.