Gpc1515

FT-IR (Thermo, NICOLET is10, Waltham, USA) was used to determine the main functional groups of the synthetic material 6s-PLGA-DAr-PO-PEG, a comparison with 6s-PLGA was done. The scanning range was 400–4000 cm⁻¹.6s-PLGA-DAr-PO-PEG was dissolved in CDCl₃ and tetramethylsilane (TMS) was used as an internal standard. The composition of polymer materials was determined by ¹H NMR (400 MHz, CDCl₃ and DMSO-d₆, δ) and ¹³C NMR (100 MHz, CDCl₃, δ) spectroscopy, which determined the species and quantity ratio of hydrogen and carbon atoms in polymer molecules. The glass-transition temperatures³⁴ within the range of 0–100 °C of 6s-PLGA and 6s-PLGA-DAr-PO-PEG were determined by Differential scanning calorimetry (DSC, TA instruments, DSC2000, New Castle, USA). Gel permeation chromatography (GPC, Waters, GPC1515, Milford, USA) was used to obtain the molecular weight.

Gel permeation chromatography (GPC1515 Waters, USA) was used to determine the molecular weights and polydispersities (PDI) with THF as the eluent at a flow rate of 0.6 mL min⁻¹ at 30 °C. Field emission scanning electron microscope (FESEM, Merlin Compact) was used to observe the surface morphology of films after being sputtered with gold using ion sputter and the energy dispersive X-ray spectroscopy (EDX) was used to map the Tb element at the film surface. The image of the fluorescent porous film was assessed by laser scanning confocal microscope (LSCM) (FV1200, Olympus, Japan) and measured by a 554 nm laser. Luminescence properties were performed on a spectrofluorometer (FLS920, Edinburgh, UK) using 323 nm excitation wavelength laser at room temperature. ¹H nuclear magnetic resonance spectroscopy (¹H NMR) spectra were carried out on a 400 MHz (Varian Mercury Plus 400) nuclear magnetic resonance instrument. The water contact angle was analyzed by a KRUSS DSA100 contact angle system with a drop size of 2.0 μL at room temperature. The structure of the samples were characterized by Nicolet-100 Fourier transform infrared spectroscopy (FT-IR) from 400 cm⁻¹ to 4000 cm⁻¹ by the KBr tablet method.