2.3.4. Transmission Electron Microscopy

Transmission electron microscopy (TEM) images of pristine and cationic CNC samples were obtained using Hitachi H-7500 operating at 80 kV in HR mode. All samples were prepared at 0.1 mg/mL in double distilled water and bath sonicated for 15 min at room temperature prior to the sample immobilization on TEM grids. 6 μL of sample were deposited on the TEM grid (Cu-300CN, Pacific Grid-Tech, San Francisco, CA, USA) with excess solution removed by using the edge of a wet filter paper. Samples were stained in 1 wt% phosphotungstic acid (PTA) in water (pH 7) for 60 s and air-dried in the dark prior to the TEM analysis. The samples were observed in the magnification range of 40,000–600,000 Å in order to provide enough information about sample purity and morphology.
