N-Substituted Poly(3,4-propylenedioxypyrrole)s:  High Gap and Low Redox Potential Switching Electroactive and Electrochromic Polymers

Abstract

A series of electrochromic N-substituted poly(3,4-propylenedioxypyrrole)s (PProDOPs) are reported, which exhibit the combined properties of a high (>3 eV) electronic band gap, colored oxidatively doped forms, and easily accessible, low redox potentials. Utilizing methyl (Me), propyl (Pr), octyl (Oct), propanesulfonated (PrS), and ethoxyethoxyethanol (Gly) pendants, the absorbance of the π−π* transition of the resulting polymers is blue-shifted when compared to the nonderivatized parent. For example, in the case of poly(N-ethoxyethoxyethanol ProDOP) (N-Gly PProDOP), this transition displays a maximum at 306 nm (onset at 365 nm), providing a colorless and highly transparent neutral polymer with a luminous transmittance greater than 99% for a film thickness of about 200 nm. N-Substituted PProDOPs display very well-defined cyclic voltammograms, with E 1/2 < −0.1 V vs Fc/Fc+ (+0.2 V vs SCE), negative of the oxidation of water, as desired for materials having stable doped forms and long-lived redox switching properties. In addition, the presence of a sulfonate group at the end of the propyl chain in N-PrS PProDOP offers the possibility of self-doping along with water solubility of the polymer. As a result, N-PrS PProDOP exhibits a fast and regular growth even in the absence of supporting electrolyte. This new family of polymers has not only shown interesting electrochromic properties in the visible. Upon doping, a very strong absorption is observed in the near-infrared (NIR) with changes in transmittance up to 97%, extending the use of these polymers as the active layer in vis−NIR switchable devices.

Preparation and characterization of polyacrylate functionalized polythiophene films

“…The pseudo-first-order kinetic plot for the RAFT polymerization showed a deviated trend which has obvious difference from the first-order kinetics ( Figure 2). From the downward curvature, we observed that the concentration of propagating radicals was decreasing [39]. Similar deviation has been reported for the RAFT polymerization of N-acryloylmorpholine [40], N,Ndimethylacrylamide [41] and sodium 6-acrylamidohexanoate [42] from the first-order kinetics.…”

Poly(3,4‐alkylenedioxypyrroles): The PXDOPs as Versatile Yet Underutilized Electroactive and Conducting Polymers

“…Table 1 illustrates the various structure-property relationships of the monomers from Scheme 2 and their respective polymers. It can be seen that the monomer oxidation potential (E p,m ) of most of the N-hydro monomers [35,37] is found between 0.95-1.20 V versus SCE (one notable exception is DMOP, with an E p,m of 0.84 V [32,43] ), whereas the N-alkylated derivatives [32,44] possess a monomer oxidation potential that is almost 200 mV lower. This phenomenon can be attributed to the N-alkyl group donating electron density into the p-system, raising the HOMO with respect to its N-hydro derivative.…”

Electrochromic Polymers

“…Linear relationships between scan rates and current intensities showed that all polymers were well adhered on ITO surface and the electrochemical processes were not limited by diffusion control [58]. A neutral state absorption maximum for P2 was recorded as 560 nm.…”