D max 2550 pc

According to our previous reported work, catechol-conjugated chitosan was synthesized in a standard EDC procedure and the CSS-Ag NPs were prepared using green methods^{9 (link)}. The CSS chemical structure was analyzed by ¹H NMR (Bruker Avance, 600 MHz, D₂O) and FT-IR (Nicolet Avatar 230 spectrometer). The phase structure of CSS was analyzed by X-ray diffraction (XRD, Rigaku D/Max-2550 PC, Japan). The silver concentration of the CSS-Ag NPs was measured by atomic absorption spectrophotometer (AAS, Hitachi 180-50, Japan). The distribution of the nanoparticles was determined in the UV-vis spectrum (Hitachi U-1000, Japan), TEM, and Malvern Zetasizer Nano ZS (United Kingdom).

The morphology of the electrospun nanofibers was observed using scanning electron microscopy (SEM) (JEOL JSM-5600LV, Japan) at an acceleration voltage of 8–10 kV. Prior to imaging by SEM, samples were sputter coated with gold for 50 s to increase their conductivity. The nanofiber diameter was obtained from at least 50 measurements on a typical SEM image using Image J 1.40 G software (NIH, USA). Further examination of nanofiber fluorescence was performed on Olympus BX51 fluorescence microscope. The nanofiber samples were prepared by collecting nanofibers on a glass slide under electrospinning nozzle for 1 min and then captured using Olympus DP72 camera equipped with Olympus CellSens software. A Nicolet-Nexus 670 Fourier transform infrared (FTIR) spectrometer (Thermo Fisher Scientific, Waltham, MA) was used to obtain the FTIR spectra of the electrospun nanofibers over a range of 500–4000 cm⁻¹ at a scanning resolution of 2 cm⁻¹. X-ray diffraction (XRD) spectroscopy was carried out on a Rigaku D/max 2550 PC (Rigaku Inc., Japan) with Cu Kα radiation. The operating voltage and current were kept at 40 kV and 300 mA, respectively. The electrospun nanofiber samples were examined between 0 and 60° (2θ) at a scanning rate of 1° (2θ) per minute.

The crystal structure and phase formation were analysed by X-ray powder diffraction (XRD) with Cu-Ka radiation (D/max 2550 PC Rigaku, λ = 0.10405 nm). The Raman spectra were obtained by confocal micro-Raman spectrometer (Renishaw InViaReflex, Gloucestershire, UK; 785 nm). The morphology of the samples was inspected using a scanning electron microscope (Hitachi SEM S-3000, Tokyo, Japan) and transmission electron microscope (Hitachi TEM H-800, Tokyo, Japan). The PL properties were measured using a fluorescent spectrophotometer (JASCO FP-6600, Tokyo, Japan). The high-temperature stability of BN nano-materials was tested using the Discovery TGA thermal analysis system (TA Instruments Q5000IR, New Castle, PA, USA; N₂ or O₂ is used as the test atmosphere (flow rate 20 mL/min), the temperature rises to 900 °C at 20 °C /min, and then changes to 10 °C /min to 1150 °C). The electronic universal material testing machine (Instron-5969, Buckinghamshire, UK; Three-point bending) was used to test the PiG samples (12 mm × 18 mm × 1.5 mm) with different components (marked with BN rations) to obtain the mechanical strength. The temperatures and infrared thermal images were recorded using an infrared thermometer (FLIR ThermoVision A40M, Wilsonville, OR, USA).

Surface morphological observations of solution blown PAA were performed with a field emission scanning electron microscope (FE-SEM, SU8010, Hitachi, Japan) after sputter-coated with 5–10 nm of gold. Fiber diameters were determined using Image Tool software (Texas City, TX, USA) by randomly selecting 100 individual fibers per specimen from at least five different SEM images with 5000× magnification. The structure of the PAA and PI membrane were confirmed by fourier transform infrared spectroscopy (FT-IR, NICOLET NEXUS-670, Waltham, MA, USA) with the attenuated total reflectance (ATR) mode. All spectra were run in 32 scan per spectrum in the range of 4000–600 cm⁻¹ with the resolution of 0.09 cm⁻¹. A wide angle X-ray diffractometer (XRD, D/max-2550 PC, Rigaku Co., Akishima, Japan) with a CuKα (λ = 1.5406 Å) was used to confirm the crystallographic structure of the sample. The diffraction angle 2θ was recorded from 5° to 60°. The tensile tests of as-prepared membranes were performed on a tensile tester (XQ-1C, Shanghai New Fiber Instrument Co., Ltd., Shanghai, China) at a crosshead speed of 10 mm/min in ambient condition. The gauge length was 10 mm and the dimensions of test specimens were 3 mm wide and 25 μm thick. Every series of samples were measured ten times.