Figure 20.

SEM images of conducting polymers after CV measurement on neural electrode: (a–d) PEDOT film; (e, f) PPy film on a neural electrode showing delamination on the edge of the polymer film. (c) Higher magnification image of (a). (d) Higher magnification image of (b). (f) Higher magnification image of (e). (g) PEDOT nanotubes. (h) PPy naotubes. PPy nanotubes and PEDOT nanotubes remained firmly attached to the neural electrode after CV measurement. The delamination height was measured as shown in (c, d and f). The delamination height was 3.7 ± 1.3 mm for PPy film and 13.4 ± 2.5 mm for PEDOT film (±s.d., n = 8). More delamination of PEDOT film was observed than for PPy film on the edges of electrode sites (p < 0.0001). PEDOT and PPy films and nanotubes were electropolymerized on the electrode site with a deposition charge density of 1.44 C cm⁻². CV measurement was carried out by applying a scanning voltage from −0.9 V to 0.5 V with a scan rate of 100 mV s⁻¹ for five cycles (Abidian et al. 2010).