Eu(III) Functionalized Crystalline Polyimide Hydrogel Film as a Multifunctional Platform for Consecutive Sensing of Spermine and Copper Ions.

In this study, a novel Eu(III) functionalized crystalline polyimide hydrogel film () is fabricated by incorporating highly stable polyimide (PI) into a sodium alginate (SA) matrix, followed by cross-linking reaction with Eu ions. Based on different fluorescence responses, is used for the consecutive detection of spermine (Spm) and copper ions (Cu). can be employed as a sensor for polyamine, especially for Spm with significant fluorescence enhancement based on the "turn on" mode. The fluorescent sensor constructed by the and Spm can be further used as a "turn off" sensor to quantitatively monitor Cu. The good selectivity combined with the low detection limit of the sensor meets the requirements for monitoring Cu. The possible luminescence response mechanisms to Spm and Cu have been studied through experimental data and theoretical calculations. In addition, a back-propagation neural network (BPNN) model based on an sensor is constructed, which can accurately distinguish Cu concentrations by deep machine learning (ML). This work not only puts forward a facile method to prepare a novel Eu-functionalized PI-based hybrid film but also demonstrates the potential of PI-based film materials for fluorescence detection.