Novel Nanocellulose/Polymer Composite Aerogel as Solid‐State Fluorescence Probe by Pickering Emulsion Route

Abstract In this study, cellulose nanofibrils (CNF)/polymer (nonwater soluble) composite aerogels are facilely fabricated using CNF‐stabilized Pickering emulsion gel technology combined with the freeze‐drying method. Pior to the formation of the O/W Pickering emulsion stabilized by the CNF, a nonwater‐soluble polymer, such as polymethyl methacrylate, polylactic acid (PLA), polycabonate, polystyrene, and so on, is dissolved into the oil phase, and the CNF are effectively dispersed in the water phase. The subsequent gelation of the Pickering emulsion through ultrasonic emulsification followed by freeze‐drying is carried out to obtain the CNF/polymer composite aerogels. The obtained CNF/polymer with a low density of ≈0.01g cm −3 have better dimentional stability and mechanical properties compared with the pure CNF aerogel. Additionally, 1,4‐dihydroxyanthraquinone (1,4‐DHAQ, a fluorophore) is loaded into the A‐CNF/PLA composite aerogel by dissolving it along with PLA into the oil phase to form a novel solid‐state fluorescence probe for Cu 2+ detection with an extremely low detection concentration of 10 −8 mol L −1 . Interestingly, neither solvent exchange nor chemical reaction (or polymerization) is required in the preparation of aerogels. This study provides a facile and universal route for the fabrication of CNF/polymer composite aerogels and the development of their functional products.