Fig. 4From: Recent advances in ion sensing with conducting polymers(Reproduced with permission from [63]. CC BY-NC-ND 3.0)Changing polymer morphology with different doping ions. Comparison of atomic force microscopy (AFM) images of the surface morphology of polypyrrole doped with different ions: a polypyrrole tetrafluoroborate; and b polypyrrole p-toluenesulfonateBack to article page