Nanosem 450 fei

The morphology and chemical composition analysis were performed using a scanning electron microscope (SEM) (Nova NanoSEM 450 FEI, Hillsboro, OR, USA) and VEGA 3 (TESCAN, Brno, Czech Republic) with an energy dispersive spectroscopy (EDS) X-ray microanalyzer INCA Energy (Oxford Instruments Analytical, High Wycombe, United Kingdom) with a magnification of 2500×, 10,000×, and 20,000×. A total of three EDS spectra were recorded for each sample, and mean values of the weight percentage of the elements were determined.

Morphological analysis of the nanostructures was carried out using field emission scanning electron microscope (Nova NanoSem 450-FEI). Briefly, 10μL of sample solutions at 100.0 (50 mg/mL for H⁺-F6-O⁻) and 5.0 mg/mL were dropped off on aluminum stub using a graphite adhesive tape. A thin coat of Au and Pd was sputtered at a current of 20 mA for 120 s. The sputter coated samples were then introduced into the specimen chamber and the images were acquired at an accelerating voltage of 2–5 kV, spot 3, through the Everhart Thornley Detector (ETD) and the Through the Lens Detector (TLD).

Morphological analysis of self-assembled peptide nanostructures, before and after heating, was carried out by field emission scanning electron microscope (Nova NanoSem 450-FEI)^{22 (link)}. Briefly, the sample solutions (5.0 mg/mL), prepared in pure MeOH, or in MeOH/H₂O mixtures (50/50 or 99.75/0.025, v/v), were placed on an aluminium stub using a graphite adhesive tape. A thin coat of gold and palladium was sputtered at a current of 20 mA for 90 s. The sputter coated samples were then introduced into the specimen chamber and the images were acquired at an accelerating voltage of 2–5 kV, spot 3, through the Everhart Thornley Detector (ETD) and the Through the Lens Detector (TLD)^{24 (link)}.