Axis nova

Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS), attenuated total reflection-Fourier-transform infrared (ATR-FTIR) spectroscopy, contact angle analysis using a sessile drop method, and gas–liquid porometry (GLP) were used to analyze the physicochemical properties of the sterile filter surface. Scanning electron microscopy (SEM, SNE-4500 M, SEC, Seoul, Korea) was used to investigate the surface and cross-sectional morphologies of the model sterile filters. An applied voltage of 15 kV and 1000× magnification was adjusted to obtain clear morphologies. For cross-section images, the samples were cut in liquid nitrogen using a sharp knife.
Surface characteristics were further investigated using Fourier-transform infrared spectroscopy (ATR-FTIR, Alpha-P FTIR spectrometer, Bruker, Billerica, MA, USA) and X-ray photoelectron spectroscopy (XPS, Axis Nova, Shimadzu, Japan) for functional group and surface chemical composition analysis. The average pore size and PSD of sterile filters were analyzed using a capillary flow porometer (Porolux 1000, Porometer NV, Nazareth, Belgium) with Porefil (15 mN/m, Alfa Wessemann Inc., West Caldwell, NJ, USA). To analyze the surface hydrophilicity of model filters, the sessile drop method was used to measure the water contact angle on the filter surface. The contact angle was measured after 5 s and 60 s of the water drop.

¹H NMR spectra were measured with a JEOL JNM ECA-500 using tetramethylsilane (TMS) as an internal standard; δ values are given in parts per million (ppm). IR spectra were measured with a SHIMADZU FTIR IRPrestige-21 spectrometer, and the values are provided in cm⁻¹. Flame atomic absorption spectrometry was conducted with a Hitachi Z-2310 polarized Zeeman atomic absorption spectrometer (AAS). X-ray photoelectron spectroscopy (XPS) was performed with a Kratos AXIS-NOVA instrument. Scanning electron microscopy (SEM) was performed using a HITACHI S-2500 instrument at an acceleration voltage of 1.5 kV. Energy-dispersive X-ray analysis (EDX/SEM) was conducted using a HITACHI S-3400N/BRUKER Quantax 200 System. Transmission electron microscopy (TEM) was conducted using a HITACHI HT-7700 instrument at an acceleration voltage of 20 kV. Samples for TEM analysis were deposited onto a Cu grid. Atomic force microscopy (AFM) was conducted with a KEYENCE VN-8010 instrument using a silicon substrate in the high amplitude mode (tapping mode) under an ambient condition.

To confirm the chemical compositions of GONs and o-SWNTs, C1s X-ray photoelectron spectroscopy (XPS) spectra were collected using an X-ray photoelectron spectrometer (AXIS NOVA, Kratos Analytical, Manchester, UK). The samples were prepared by dropping a dispersion of GONs or o-SWNTs onto a silicon wafer (4 WAFER P-100, Sehyoung Wafertech, Seoul, Korea) and then drying repeatedly.

The chemistry of the TMDSO films was analysed by XPS with an AXIS Nova (Kratos Analytical Inc., Manchester, UK) with a monochromated Al Kα X-ray source (λ = 1486.6 eV). The X-ray spot size was a slot with dimensions of 700 μm × 300 μm. The pressure within the analysis chamber during analysis was typically below 10⁻⁸ mbar. The photoemission angle of 0° corresponded to a 90° take-off angle respective to the surface. The survey and high-resolution C 1s spectra were collected at pass energies of 160 eV and 20 eV, respectively, and scan times of two minutes with two sweeps each. Three spots were analysed per sample with the electron gun used for charge neutralization. The acquired spectra were analysed using Casa XPS software version 2.3.15 (Casa Software Ltd., Cheshire, UK), with element quantification based on the standard relative sensitivity factors provided by the manufacturer. The spectra were calibrated using the hydrocarbon (C-C) to 285 eV.

The XPS analysis before and after use of the file (n = 3/group) and Ni/Ti control was performed using Axis-NOVA (Kratos, UK) with a monochromatic Al Kα X-ray source (1486.6 eV) and an aluminum mode. A pass energy of 20 eV with energy steps of 0.2 eV step⁻¹ was maintained for the photoelectron spectra. The photoelectron take-off angle was 90° between the sample surface and the axis of the analyzer lens with the aperture of spectrometer set at 300 × 700 µm². Charging effect compensation was done using the magnetic immersion lens of a flood gun, in the XPS instrument. Depth profiling was done using Ar ions at 3000 eV in each 10 s cycles. Data was fit using Smart peak ground parameters in Avantage 5.9 software. Calibration was done by setting the C 1 s signal peak from impurities (284.8 eV.).