Highly fluorescent cotton fiber based on luminescent carbon nanoparticles via a two-step hydrothermal synthesis method

A kind of highly fluorescent cotton fibers, in which the luminescent carbon nanoparticles (CNPs) are generated in the lumen and the mesopores directly, have been prepared by the method of hydrothermal synthesis in situ using citric acid and urea as raw materials, and hexadecyl trimethyl ammonium bromide and tributyl phosphate as active agents. The CNPs/cotton fibers were characterized by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS), respectively. The optical properties are investigated by fluorescence spectrofluorometry and PR-305 long afterglow phosphors tester. The results showed that the CNPs were self-assembled successfully in the lumen as well as in the mesopores of cotton fibers. The CNPs/cotton fibers could emit bright and colorful photoluminescence under excitation lights of different wavelengths. The afterglow decay process could be divided into fast decay and slow decay stages and the emission of CNPs/cotton fiber had two peaks at 450 nm and 570 nm respectively when the wavelength of excitation changed from 310 nm to 500 nm. The preparation of highly fluorescent cotton fibers by self-assembly method has great significance to the functionalization of cotton fibers.