LAUSR

Abstract In this work, a novel fluorescent smart hydrogel based on carbon dots (CDs)/hydrogel nanocomposite material for stable Fe3+ ion detection was prepared. The CDs were firstly modified by polyethyleneimine (PEI) and then immersed into microcrystalline cellulose (MCC) hydrogel. The obtained PEI-CDs were well characterized for their morphological features, chemical composition and optical properties by transmission electron microscopy and different spectroscopic analysis. The smart hydrogel nanocomposite was characterized by scanning electron microscopy, fluorescence spectrophotometer, infrared spectroscopy as well as thermogravimetric analysis. The results revealed that the prepared PEI-CDs were spherical in shape and monodispersed in water with a quantum yield of 28%. The smart PEI-CDs/MCC hydrogel exhibited a better photo-stability than single PEI-CDs by avoiding their self-quenching. Moreover, there existed interactions between PEI-CDs and MCC hydrogel, which could enhance the cross-linking degree of MCC hydrogel, resulting in improved mechanical and thermal properties of nanocomposite. This easy prepared fluorescent smart hydrogel is an attractive material for stable Fe3+ ion sensing application.