Transmission Electron Microscopy of the MWCNT/PDMS nanocomposite

Cryogenic Transmission Electron Microscopy (cryo-TEM) imaging was performed using a Tecnai F20 X TWIN microscope (FEI Company, Hillsboro, OR, USA) which operates using a field emission gun at an acceleration voltage of 200 kV. Images were collected by a Gatan Rio 16 CMOS 4k camera (Gatan Inc., Pleasanton, CA, USA) and then processed with Gatan Microscopy Suite (GMS) software version 3.31.2360.0 (Gatan Inc., Pleasanton, CA,USA). Samples were prepared by vitrification of aqueous solutions placed on cooper grids covered with a carbon film (Quantifoil R 2/2; Quantifoil Micro Tools GmbH, Großlöbichau,Germany). Prior to use, the grids were activated for 15 s with an oxygen plasma using aFemto plasma cleaner (Diener Electronic, Ebhausen, Germany). Cryogenic samples were prepared by applying a drop (3 μL) of the suspension to the grid, then blotting with filterpapers and immediately plunged in liquid ethane using a fully automated Vitrobot MarkIV desiccant device (Thermo Fisher Scientific,Waltham, MA, USA). The vitrified specimens were stored in liquid nitrogen until placed in a cryo-TEM holder (Gatan 626; Gatan Inc.,Pleasanton, CA, USA) and analyzed at −178 ◦C in the TEM.