Experimental observation of large-size fractals in ion-conducting polymer electrolyte films

We have succeeded in growing large-size fractals (∼2–3 cm) in solution-casted ion-conducting polymer films of polyethylene oxide doped with ammonium iodide. These are shown to be ‘‘diffusion-limited aggregates’’ due to iodine ions in random walk. This mechanism is supported by energy dispersive x-ray analysis, x-ray diffraction, optical absorption, polarization, and complex impedance studies.