Tecnai g2 12 twin tem 120 kv

Nanobubbles in salt solution were visualized using an FEI- Tecnai G2 12 Twin TEM 120 kV equipped with a low-temperature Gatan unit. The nanobubble samples were prepared for Cryo-TEM analysis by placing 1μL of nanobubble solution onto the holey carbon-coated gold grid, and it is further vitrified into the liquid ethane by using Vitrobot(FEI Company). Subsequently, the grid containing the vitrified nanobubbles has been placed onto the Cryo holder, and images were taken at an acceleration voltage of 120 kV at temperature −174 °C. Nanobubbles generated during the dissolution of NaCl with 1 mM salt concentration have been characterized by Cryo-TEM as shown in Fig. 1a. Evidently, the spherical nanobubbles are visualized by Cryo-TEM; however, the size of nanobubbles is larger than that of the NTA measurement as shown in 3-D histogram in Fig. 1b.Fig. 1

(a) Cryo-TEM micrograph of nanobubbles in 1 mM of NaCl solution (b) 3D histogram of bubble count, size and light scattering intensity in nanobubble sample of 1 mM NaCl.