Dsa100 contact angle system

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.