Nanoscope 5 multimode atomic force microscope

For GO functionalization, 2 mg of GO was diluted in 2 ml ultrapure DI (Deionized) water and then added 20 mg PEG-NH2. Put those mixtures under sonication for 90 min. Then, the mixture was mixed with 20 mg EDC and stirred for 12 h. Afterward, centrifuged at 20000 rpm for 30 min to remove excess free PEG-NH2. At last, resuspended the precipitate into 2 mL ultrapure DI water. The rGO-PEG was synthesized in the presence of GO-PEG and NaBH4. Last, rGO-PEG with the final concentration of 2 mg/mL was achieved after centrifugation to remove excess free reagents.
The TBK1si/rGO-PEG was diluted with distilled water, put on a copper grid with nitrocellulose, and then stained with phosphotungstic acid. Afterward, it was measured by Nano ZS-90 (Malvern Instruments, Malvern, UK) under room temperature. AFM (atomic force microscopy) images were taken by a Nanoscope V multimode atomic force microscope (Veeco Instruments, USA). TBK1si/rGO-PEG was diluted with ultrapure DI water with a final concentration of 1 × 10⁻⁶ M for AFM. Twenty μL TBK1si/rGO-PEG sample was placed on the brand new muscovite mica and dried the samples under critical point dryer. Photos were taken in the tapping mode under room temperature.

The SEM images were taken with Hitachi- S4160 scanning microscope (Tokyo, Japan) to survey the morphological pattern and surface structural aspects of GO and Fe₃O₄@SiO₂-GO nanocomposite. A Nanoscope V multimode atomic force microscope (Veeco Instruments, USA) were used to perform AFM measurements. The AFM images were taken from samples which prepared by deposition a dispersed GO/methanol solution (70 mg mL⁻¹) onto a mica surface and allowing them to dry in air [25 (link)]. The images were taken under ambient condition by adjusting the instrument on the tapping mode.

Drops of aqueous suspensions (0.2 wt.%) of BNC, VNC, AcBNC, and AcVNC were placed on a mica support and analyzed using a Nanoscope V-Multimode atomic force microscope (Veeco, Santa Barbara, CA, USA) in tapping mode (intermittent contact) using a silicon nitride probe Arrow-NCR-50 (Nano World, Neuchâtel, Switzerland). The resonance frequency of the cantilever was 258 kHz, with a constant force of 42 N m⁻¹ and a tip radius ranging from 5 to 10 nm. Scanning frequencies typically ranged from 1.0 to 1.5 Hz.