Fluorescent and stimuli-responsive cellulose nanocrystals (CNC) were prepared via covalent conjugation of a 1, 8-naphthalimide dye onto TEMPO-oxided CNC. The structural and morphological integrity of CNC were essentially not affected by the functionalizaiton, in spite of their relatively high dye content of 0.1 ± 0.01 mmol g⁻¹. The dye-labeled CNC show much higher fluorescence sensitivity to solvent polarity and ion concentration compared to pure dye. The fluorescence emission of dye-labeled CNC is greatly enhanced when reducing solvent permittivity or increasing ionic strength. The magnified fluorescence responsiveness is attributed to the effect of aggregation-enhanced emission (AEE) based on the sensitive colloidal stability of CNC to medium conditions. Under high ionic strength and low solvent permittivity, the compressed double layers of CNC lead to space restriction and steric hindrance of dye groups, which limit the process of nonradiative transition. The aggregation of CNC triggered by the change of ion concentration was supported by dynamic light scattering (DLS) particle sizes and Zeta potential values. Owing to the special AEE effect, the fluorescent CNC are promising sensing nanomaterials for wide applications.

荧光和刺激响应性纤维素纳米晶体（CNC）是通过将1，8-萘二甲酰亚胺染料共价缀合到TEMPO氧化的CNC上制备的。尽管它们的染料含量相对较高，为0.1±0.01 mmol g ^-1，但CNC的结构和形态完整性基本上不受功能化的影响。。与纯染料相比，染料标记的CNC对溶剂极性和离子浓度显示出更高的荧光敏感性。当降低溶剂介电常数或增加离子强度时，染料标记的CNC的荧光发射会大大增强。基于CNC对中等条件的敏感胶体稳定性，放大的荧光响应性归因于聚集增强发射（AEE）的影响。在高离子强度和低介电常数的情况下，CNC的压缩双层会导致空间限制和染料基团的空间位阻，从而限制了非辐射跃迁的过程。动态离子散射（DLS）粒径和Zeta电位值支持了由离子浓度变化触发的CNC聚集。由于特殊的AEE效果，