Preparation Of Multicolor Fluorescent Carbon Quantum Dots And Construction Of Fluorescent Nylon Fabric

With the continuous development of human society,fluorescent textiles appear more and more frequently in daily life.Fluorescent textiles have been widely used in many fields,such as textile and clothing,anti-counterfeiting,safety marking,inspection and detection,because of their excellent characteristics.Carbon quantum dots are one of the fluorescent carbon nano materials that have attracted much attention in recent years.Due to their excellent optical properties,low toxicity,environmental friendliness and easy preparation,they have become a hot spot in the research of fluorescent materials in recent years and have great development potential.In this paper,the effects of vacuum method,solid phase method and solvothermal method on the morphology,surface groups and optical properties of carbon quantum dots were studied,and the effects of external field conditions such as temperature,p H value and concentration of carbon quantum dots on the preparation of carbon quantum dot based fluorescent textiles were discussed.At the same time,the relevant mechanisms were discussed by means of transmission electron microscope,fluorescence spectrum,infrared spectrum and X-ray photoelectron spectroscopy,it is expected to provide technical and theoretical support for the preparation of high-quality carbon quantum dots and their application in fluorescent textiles.The specific research contents include the following aspects:1.Yellow green and orange red fluorescent carbon quantum dots were synthesized by vacuum method,solid phase method and solvothermal method respectively.The effects of different preparation methods on the morphology,surface groups and optical properties of carbon quantum dots were studied by means of fluorescence spectra,UVVis absorption spectra,Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy.The results show that different preparation methods have certain effects on the morphology of carbon quantum dots.The average particle size of carbon quantum dots by vacuum method is 8.08 nm,that by solid state method is 3.28 nm,and that by solvothermal method is 3.87 nm;Different preparation methods have significant effects on the optical properties of carbon quantum dots.The fluorescence peak of carbon quantum dots by vacuum method is 524 nm,the absorption peak is at407 nm,the fluorescence lifetime is 16.0 ns,and the quantum efficiency is 60.6%.The fluorescence lifetime of carbon quantum dots by solid phase method is 15.2 ns,and the quantum efficiency is 57.1%.The fluorescence peak and absorption peak are basically the same as those of carbon quantum dots by vacuum method.The absorption peak of carbon quantum dots by solvothermal method is 469 nm,and the fluorescence peak is at 564 nm,the fluorescence lifetime is 13.4 ns and the quantum efficiency is 17.8%;The preparation methods have a significant effect on the surface groups of carbon quantum dots.The surface of carbon quantum dots by solvothermal method is rich in hydroxyl groups,and the surface of carbon quantum dots by vacuum method and solidstate method is rich in carboxyl groups and amino groups.2.The influence of the preparation process on the optical properties of fluorescent nylon fabric was studied.The preparation process has almost no effect on the fluorescence peak and absorption peak.The fluorescence peak and absorption peak of carbon quantum dot fluorescent nylon fabric by vacuum method are 524 nm and 405 nm respectively.The fluorescence peak and absorption peak of carbon quantum dot fluorescent nylon fabric by solid state method are 524 nm and 407 nm respectively.The fluorescence peak and absorption peak of carbon quantum dot fluorescent nylon fabric by solvothermal method are 564 nm and 469 nm respectively;the preparation process has no significant effect on the fluorescence lifetime.The fluorescence lifetime of carbon quantum dot fluorescent nylon fabric by vacuum method is 15.2 ns,that of carbon quantum dot fluorescent nylon fabric by solid state method is 14.8 ns,and that of carbon quantum dot fluorescent nylon fabric by solvothermal method is 15.6 ns;the preparation process has a significant impact on the quantum efficiency.The quantum efficiency of carbon quantum dot fluorescent nylon fabric by vacuum method is 30.6%,that of carbon quantum dot fluorescent nylon fabric by solid state method is 42.8%,and that of carbon quantum dot fluorescent nylon fabric by solvothermal method is 8.8%,which is 33%～50% lower than that before combination.3.The effects of preparation temperature,concentration of carbon quantum dots and p H value on the fluorescent properties of nylon fabric were systematically studied.The results show that when the external field condition is 26℃,the p H value is 2～3,and the concentration of carbon quantum dots is 10 g/L,the fluorescence of nylon fabric is the strongest.4.In this paper,the mechanism of the combination of carbon quantum dots and nylon was preliminarily explored.The fluorescent nylon fabric was characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and washing fastness testing machine.Through the analysis and comparison of the test results,it was found that the combination of carbon quantum dots and nylon fiber may be mainly through the interaction of ion bond,van der Waals force and hydrogen bond.