Fig. 4. SEM images of a cross-setion and EDS mapping of samples: (A) PTFE, (B) PTFE-DA, (C) PTFE-DA eluted with a 1.0 M HCl solution, (D) PTFE-DA eluted with a 1.0 M NaOH solution, (E) PTFE-DA/PEI, (F) PTFE-DA/PEI eluted with a 1.0 M HCl solution, and (G) PTFE-DA eluted with a 1.0 M NaOH solution. Red = carbon, green = nitrogen, light blue = oxygen, purple = fluorine.
