Microwave synthesis of amphiphilic carbon dots from xylose and construction of luminescent composites with shape recovery performance

Abstract Carbon dots (CDs) have sparked tremendous attention owing to their unique properties and great potential in various fields. Herein, novel amphiphilic CDs (ACDs) were synthesized solvothermally by microwave heating a mixture of xylose and ethylenediamine in N, N-dimethylacetamide. The xylose-derived ACDs were monodisperse nanoparticles with an average diameter of about 1.81 nm, and exhibited excitation-dependent emission behavior in both aqueous and several common organic solvents. Furthermore, the synthesized ACDs can be uniformly dispersed into polyvinyl alcohol (PVA) solution to fabricate transparent luminescent composites, the as-prepared PVA/ACDs composites not only exhibited excellent fluorescence with excitation-dependent emission performance, but also achieved water-induced shape memory behavior. The intrinsic reason and pH sensitivity of shape recovery were investigated, the results confirmed that a faster shape recovery can be obtained in water at pH 4 within 180 s. Further investigation illustrated that the sensitivity of additional hydrogen bonding between PVA and ACDs to the water molecular was highly related to the shape recovery of the luminescent composite. The green synthesis route for xylan-derived ACDs and fabrication of smart luminescent composite will open many possibilities for the valuable application of low-cost biomass.