1：Experimental Design and Method Selection:

The study involved synthesizing Eu-complex polyurethane foams (Eu-PUFs) via a one-step co-polycondensation reaction to create a porous material for sensing Cu2+ ions. The design rationale was to use covalent bonding to integrate probe molecules into the polymer matrix to prevent leaching and enable reusability in aqueous environments. Theoretical models included photoluminescence spectroscopy for sensing and Stern-Volmer equation for quenching analysis.

2：Sample Selection and Data Sources:

Samples included Eu-PUFs with varying concentrations of Eu-complex (0%, 0.5%, 1%, 1.5%, 3%, 5%). Metal ion solutions (e.g., Cu2+, K+, Zn2+, etc.) were prepared in pure water for testing selectivity and sensitivity. Data were sourced from laboratory synthesis and measurements.

3：5%, 1%, 5%, 3%, 5%). Metal ion solutions (e.g., Cu2+, K+, Zn2+, etc.) were prepared in pure water for testing selectivity and sensitivity. Data were sourced from laboratory synthesis and measurements. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Fourier Transform Infrared (FT-IR) spectrometer (Nicolet Is-10), thermogravimetric analyzer (TA Q50), mass spectrometer (LCQ DECA XP), NMR spectrometer (DRX-400 MHz, Bruker), UV-Vis-NIR spectrophotometer (Shimadzu UV-3600), fluorescence spectrophotometer (Shimadzu RF-5301PC), and steady state spectrometer (FLS980). Materials included europium complexes, polyurethane precursors (polyhydric alcohol, polyethylene glycol, biphenyl-methane-diisocyanate (MDI)), catalysts (dibutyltin dilaurate), and metal salts.

4：0). Materials included europium complexes, polyurethane precursors (polyhydric alcohol, polyethylene glycol, biphenyl-methane-diisocyanate (MDI)), catalysts (dibutyltin dilaurate), and metal salts. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis of probe molecule Eu(TTA)3?Phen-NH2 from Eu(TTA)3?2H2O and Phen-NH2. Preparation of Eu-PUFs by co-polycondensation reaction. Characterization using FT-IR, TGA, UV-Vis, PL spectra, and luminescence decay measurements. Sensing experiments involved immersing Eu-PUFs in metal ion solutions, recording emission spectra, and testing reversibility with EDTA washing.

5：Preparation of Eu-PUFs by co-polycondensation reaction. Characterization using FT-IR, TGA, UV-Vis, PL spectra, and luminescence decay measurements. Sensing experiments involved immersing Eu-PUFs in metal ion solutions, recording emission spectra, and testing reversibility with EDTA washing. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using luminescence intensity measurements, Stern-Volmer equation for quenching constant (KSV) calculation, and quantum efficiency (η) determination from decay profiles. Statistical analysis included linear regression for LOD calculation.