Escalab 220ixl

Scanning electron microscopic (SEM) images were obtained using a QUANTA200 instrument. Fourier transform infrared spectroscopy (FT-IR) was performed on a Spectrum 400 instrument over the scan range 550–4000 cm⁻¹. Atomic force microscopic (AFM) images were obtained using a Bruker Dimension Icon instrument. X-ray diffraction (XRD) analysis was carried out using a XRD-6100 over the scan range 5–60° and scan speed of 5°/min. All the X-ray photoelectron spectroscopic (XPS) measurements were taken using an ESCALab220i- XL instrument (Thermo Scientific) with a monochromatic Al Kα X-ray source. The mechanical properties were measured in tensile mode using an AI-7000S TC160701511 tester at a loading rate of 1 mm/min with a gauge length of 5 mm. All the samples were cut into strips, 20 mm long and 3 mm wide, before conducting the measurements, and the test results were the average measurements values for all the samples. The thicknesses of all the samples were confirmed using a thickness gauge. The values of tensile strength and strain were derived from the stress–strain curves. The values of toughness were obtained by calculating the integral areas under the curves. A standard two-probe method using a source meter (CHI760E) was employed to measure the electrical conductivities of the artificial nacre specimens.

18 mm round glass coverslips (VWR, 48380-046) were cleaned and functionalized by exposure to an oxygen plasma generated by a Harrick plasma cleaner (model PDC-32G) utilizing high purity oxygen gas. The surfaces were then submersed in a reaction solution of 1% v/v of trimethoxysilylpropyldiethylenetriamine (DETA, United Chemical Technologies, Inc., T2910-KG) in dry toluene (VWR, BDH1151-4LG) and heated to just below the boiling point of toluene over a period of 30 minutes. The reaction vessel was removed from heat and allowed to cool for 30 minutes, and then rinsed in 3 serial toluene baths. Next, the surfaces were placed in dry toluene and heated to just below the boiling point of toluene over a period of 30 minutes. After the second heating step, the surfaces were cured in an oven at approximately 110 °C overnight (~15 hr). Derivatized surfaces were characterized by contact angle goniometry, with a 5 µL droplet of water, and by X-ray photoelectron spectroscopy using a Thermo Scientific ESCALAB 220i-XL instrument with aluminum Kα X-rays and a 90° take-off angle^{52 (link),53 (link)}.

Microscopic morphologies were characterized by a scanning electron microscope (FEI Nova Nano SEM 450). The crystal structure of the prepared samples was studied by a PANalytical Empyrean II X-Ray diffractometer (XRD) with a Cu Kα radiation source (λ=1.54060 Å). X-ray photoelectron spectroscopy (XPS) measurements were done using a Thermo Scientific (ESCALAB220i-XL) instrument with a monochromatic Al Kα X-ray source at 1486.68 eV. The presented XPS data and binding energies were calibrated by the carbon 1 s peak at 284.6 eV. The high-resolution transmission electron microscopy (HRTEM) images and corresponding energy-dispersive X-ray spectroscopy (EDX) mapping results were obtained using FEI Talos FE200x G2 instrument. The optical absorption properties of the samples were recorded using a UV–Vis–NIR spectrophotometer equipped with an integrating sphere (UV-3600, Shimadzu).

XPS measurements
were carried out on an ESCALAB 220iXL (Thermo Fisher Scientific) spectrometer
equipped with a monochromated Al Kα X-ray source (E = 1486.6 eV). The pellets were prepared on a stainless-steel holder
with conductive double-sided adhesive carbon tape. Before survey and
detailed analysis, samples were exposed to Argon sputtering with 2
kV at a pressure of 2 × 10^–7 mbar Ar. Sputtering
was carried out for 10 min and then for 180 min to ensure the removal
of any contaminants from the surface. The electron binding energies
were obtained without charge compensation, and no further referencing
has been applied. For quantitative analysis, the peaks were deconvoluted
with Gaussian-Lorentzian curves using the software Unifit 2023. The
peak areas were normalized by the transmission function of the spectrometer
and the element-specific sensitivity factor of Scofield.³⁵

The chemical forms of the functional groups were analyzed using FT-IR (Nicolet iS50, Thermo Scientific Co., Waltham, MA, USA) and XPS (ESCALab220i-XL, Thermo Scientific Co., Waltham, MA, USA). The microstructure of the sample was characterized by SEM and energy dispersive spectroscopy (EDS) (FEI/Philips XL30, Phenom ProX, Royal Dutch Philips Electronics Ltd., Amsterdam, The Netherlands). Zeta potential of the adsorbent was measured by a high sensitivity Zeta potential analyzer (Brookhaven Instruments Co., Austin, TX, USA). The concentrations of metal ions were detected by an inductively coupled plasma optical emission spectrometer (ICP) (Leeman Prodigy 7, Teledyne Leeman Labs., Hudson, NH, USA).