One-step hydrothermal synthesis of fluorescent nanocrystalline cellulose/carbon dot hydrogels

Fluorescent nanocrystalline cellulose/carbon dots (NCC/CDs) hydrogels were successfully prepared by a facile one-step green hydrothermal carbonization process. The properties of NCC/CDs hydrogels prepared at different temperatures were investigated by fluorescence spectroscopy, transmission electron microscopy, nuclear magnetic resonance spectroscopy, X-ray diffraction, and thermogravimetric analysis. NCC/CDs hydrogels with high crystallinity, high thermal stability, and excellent fluorescence properties can be obtained by controlling the hydrothermal treatment temperature. Small rod-like NCC/CDs hydrogels with a diameter of 2-6 nm, a length of 40-60 nm, and the cellulose Ι structure were obtained when the hydrothermal carbonization temperature was 240 °C. The NCC/CDs hydrogels exhibited an excellent broad spectral response and high fluorescence stability at various pH values. Considering of the wide natural abundance of NCC and the biocompatibility of the NCC/CDs hydrogels, Preparation in this simple, green approach is attractive for future bio-medical applications.