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The surface morphology of nanofibers was investigated using a field-emission scanning electron microscope (FE–SEM, Sigma, Zeiss Germany). Particle size and particle size distribution were determined by image analysis using an optical microscope (using the free Scion software) on a computer equipped with the Global Lab Image software, in the optical microscope, Jenaval–Carl Zeiss (Germany). The contact angle between nanofiber mats and the liquid phase was measured using the static digital method described in the standard D5725-97 (ASTM, 2003). To do this, an optical microscope (Olympus SZ-STU2) equipped with a digital camera (Olympus Camedia C-3040) was used. The FTIR spectrum of samples was examined by the FTIR spectroscopy (ThermoNicolet NEXUS 870 FTIR from Nicolet Instrument Corp., USA). The thermal degradation analysis (TGA) of the samples was performed on a TGA-PL thermoanalyzer from UK. In each case, a 5 mg sample was examined under N₂ at a heating rate of 5°C/min from room temperature to 650°C.

The nanostructures used in this research were characterized using Fourier transform infrared (FTIR) spectrometer (Perkin Elmer, UK), Energy-dispersive X-ray spectroscopy (EDS) (FESEM, Sigma VP, ZEISS, Germany), Transmission electron microscopy (TEM, Zeiss-EM10C-100 kV, Germany), and X-ray diffraction spectroscopy (XRD) (Siemens D5000 diffractometer, Karlsruhe, Germany).

The homogenous polymer patterns were obtained by laser interference photolithography using a Lloyd’s mirror interferometer. The interferometer generated light interference between light coming from a source (MXL-FN-360) and the reflected light from the mirror. First, ITO-coated glass (10 Ω/cm², 0.5 mm thickness) was washed in 1% Triton X-100, deionized water, and 80% ethanol for 15 min and sonicated and dried using N₂.
The washed ITO glass was coated with HMDS using spin coating and this HMDS-coated ITO glass was coated with the diluted PR and thinner (ratio of 6:4). This obtained substrate was then baked on a hot plate at 130 °C for 60 s (soft bake). The soft-baked substrate was exposed to UV (λ = 360 nm, 0.51 mW) using the Lloyd’s mirror interferometer. The substrate was exposed twice to UV to obtain PR nanohole patterns. The exposed substrate was then baked again under the same conditions as the soft bake (post-exposure bake). Subsequently, the substrate was treated in the developer to remove the unexposed PR and was washed with DI water. Further, the washed substrate was baked at 135 °C for 60 s (hard bake).
The PR patterns and CAuNE substrates were imaged by field emission scanning electron microscopy (FE-SEM, SIGMA, Zeiss, Germany) at an acceleration voltage of 10 kV.

FE‐SEM (Sigma‐500, Sigma, Germany) was used to examine the sample morphology and EDS; XRD showed the composition and phase. Nanoindentation was employed to assess the adhesion strength between the coatings and substrates. UV–vis spectrophotometry was performed on UV‐3600 (Shimadzu, Japan), and TEM ( FEI, TF20, USA) was performed to examine the morphology. The cell morphology was observed under an inverted fluorescence microscope (IX73, Olympus, Japan).

Powder X-ray diffraction (XRD) patterns were measured on a Phillips X’Pert PRO using filtered Cu Kα radiation (λ = 1.54178 Å) in the range of 2θ = 10–80°. The surface morphology of graphene oxide was characterized by field emission-scanning electron microscopy(FE-SEM, Sigma, Zeiss) with an acceleration voltage of 15 kV. Fourier transform infrared (FT-IR) spectra (4000–400 cm⁻¹) were taken using a Tensor 27 spectrometer (Bruker, Saarbrucken, Germany).