Iridium oxide soft composite coatings exhibit a markedly reduced impedance, and increased CSC and CIC compared to bare Au. By increasing the pulse Figure 1. (a) Impedance spectrum and (b) cyclic voltammogram of the IrOx-PDMS coating. The inset shows a micrograph of the electrode (0.7×2 mm~2). Figure 2. Voltage transients measured with a pulse width from (a) 100 to 500 μs, (b) 600 to 1000 μs and (c) 1000 to 3000 μs, respectively. Figure 3. (a) Most negative and positive polarizations of electrode interface with pulse width from 100 to 3000 us; (b) Cathode and anode potentials with pulse width varying from 100 to 3000 us; (c) Ratios between electrode-electrolyte interfaces and electrode potentials as a Junction of pulse width; (d) Injected current amplitude and injected charge as a function of pulse width (mean ± std dev., n=6) width to 3000 us, the available charge that can be injected in the safe range almost doubles. Average ratios between electrode-electrolyte interfaces and electrode potential reach 90.1 % (negative) and 70.3 % (positive) at 3000 us pulse width, respectively. By using wider pulse width, the absolute values of cathode and anode driving potentials decrease significantly for a given charge. Thus, the risks of electrode corrosion and water reduction/oxidation are also reduced. These considerations suggest that the iridium oxide soft composite coating may be a promising material for implantable neural interfaces.
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