Fig. 1: Materials characterization of PProDOT and PEDOT polymer thin films.

a Repeat unit structures of electropolymerized PEDOT:PSS (PEDOT-epoly), commercial PEDOT:PSS dispersions (PEDOT-spin), oligoether functionalized ProDOT copolymerized with 2,2-dimethyl ProDOT [P(OE3)-D], and oligoether functionalized ProDOT copolymerized with unsubstituted EDOT [P(OE3)-E]. b Atomic Force Microscopy (AFM) images of PEDOT-epoly, PEDOT-spin, P(OE3)-D, and P(OE3)-E thin films. Scale bar = 200 nm. Each experiment was repeated independently with similar results at least 3 times. c. Color change of PEDOT-epoly, PEDOT-spin, P(OE3)-D, and P(OE3)-E thin films at −300 mV, 0 mV, and +300 mV. Scale bar = 5 mm. d Visible-near infrared (Vis-NIR) spectroelectrochemistry of PEDOT-epoly, PEDOT-spin, P(OE3)-D and P(OE3)-E thin films from −600 mV to +600 mV in HEPES buffered Tyrode’s salt solution. e Normalized Vis-NIR absorbance change of PEDOT-epoly (green hexagon), PEDOT-spin (yellow triangle), P(OE3)-D (pink circle), and P(OE3)-E (blue diamond) films at 561 nm. The dashed line indicates zero bias potential. f Cyclic voltammograms of different polymer films measured at a scan rate of 200 mV/s on ITO glasses in HEPES buffered Tyrode’s salt solution. The y-axis is scaled to focus on the faradaic current below 0.7 V. g Active sites concentration in different polymer thin films estimated from the reductive current of cyclic voltammetry. Data are presented as mean ±SD; n = 3 polymer films.