Axis his spectrometer

After being immersed in deionized water for 7 days and then dried, uncoated DMLS-Ti samples and DMLS-Ti samples of each film layer were analysed by XPS on an AXIS His spectrometer (Kratos Analytical Ltd., UK) to identify the chemical compositions. The contact angle of each layer with ddH₂O and SBF was measured using a drop-shape analysis system (JC2000D1, Micaren, China) at room temperature. The mean static contact angle of each Ti surface was determined from measurements performed in triplicate.
The surface microstructure morphology of the SLA Ti, DMLS-Ti and the multilayer films was evaluated field-emission SEM (SUPRA 55 SAPPHIRE, Germany) with an energy-dispersive X-ray spectrometer (EDX, Germany).
The stiffness and Young’s modulus of the DMLS-Ti and the multilayer films were determined via a nano-indentation analysis. To increase measurement reliability, the highest central point was selected for the loading-unloading sequence in the experiment. The load and displacement of the indenter were continuously monitored. The hardness was derived by dividing the load by the area of contact. The slope of the unloading curve provided a measure of the elastic modulus.

The exfoliation mixture was first centrifuged at 2500 rpm to remove large graphite particles and possible planktonic microorganisms, and then the supernatant was filtered through a 0.1 μm Durapore PVDF filter (Millipore Co.,). The remaining solid materials on the filter were washed with the following sequence: 18 MΩ water, 80% ethanol, 18 MΩ water, 1 N HCl, and 18 MΩ water again. The resulting materials called BEGO were re-suspended in 18 MΩ water for characterization. UV-vis absorption spectra were recorded using a Thermo GENESYS 10S UV-vis spectrophotometer. Fourier transform infrared spectroscopy (FT-IR) was performed by using a Thermo-Nicolet FT-IR Avatar 370 spectrometer. XPS analysis was carried out by a Kratos Axis His spectrometer. Raman spectra were obtained by Raman Microscope with wavelength of 532 nm and a 100 × objective. Atomic force microscopy (AFM) images were generated on a VEECO Dimension 3100. Transition electron microscopy (TEM) and electron diffraction images were obtained using a FEI Tecnai G20 electron microscope. Samples for AFM and TEM imaging were prepared by drop-casting the dispersion onto freshly cleaved mica substrates and lacey carbon TEM grid, respectively, which were then air dried under ambient lab conditions.