Fourier-transform infrared, (1)H nuclear magnetic resonance, X-ray photoelectron spectroscopy and gel permeation chromatography reasserted the formation of CS-FU. The result exhibited that, oxidation degree of FU, degrees of substitution, average molecular weight and yield of CS-FU were 25 %, 10 %, 23 kDa and 45 ± 0 %, respectively. reading electron microscopy disclosed