Low-potential electrosynthesis of a novel nitrogen analog of PEDOT in an ionic liquid and its optoelectronic properties

Electropolymerization of EDOT in an anionic surfactant-stabilized hydrophobic ionic liquid-based microemulsion

Here, an anionic surfactant [AOT]^- (bis-(2-ethylhexyl) sulfosuccinate)-stabilized H₂O/[Omim][PF₆] (1-octyl-3-methylimidazolium hexafluorophosphate) microemulsion has been tested for the first time as a medium for the electropolymerization of 3,4-ethylenedioxythiophene (EDOT). To formulate AOT-stabilized [Omim][PF₆]-based microemulsions of different water contents, the phase triangle was determined at 35 °C. Measurements of the conductivities of the microemulsions, their solubilization capacities toward EDOT and their catalytic effects on EDOT electrooxidation show that the present [AOT]^--stabilized ionic liquid microemulsion is a good medium for EDOT electropolymerization. Studies on the process of the electropolymerization of EDOT in this [Omim][PF₆]-based microemulsion indicate that the water content (i.e., microstructure) of the microemulsion medium is an important factor affecting the onset potential and the deposition rate of the PEDOT. The morphology and the doping level of the as-prepared PEDOT are also found to be correlated with the water content of the ionic liquid microemulsion. The microemulsion with higher water content results in a PEDOT with better electroactivity and higher doping levels. FTIR spectra and XPS analysis show that the PEDOT electrosynthesized in the microemulsion is co-doped by both [AOT]^- and [PF₆]^-. Compared with the neat [Omim][PF₆], the use of the ionic liquid microemulsions can reduce not only the consumption of the expensive ionic liquid, but also the onset potential for the electrooxidation of EDOT. Moreover, by tuning the water content of the medium, the electropolymerization of PEDOT and its electrochemical properties could be regulated accordingly. Under the identical deposited charge, the PEDOT originated from the high water content microemulsion (50% H₂O μE) has a higher specific capacitance (124 F g^-1) than that from neat [Omim][PF₆] (117 F g^-1). It follows that the present ionic liquid microemulsion is a good medium for EDOT electropolymerization. The present study opens up a new route for the green and low-cost electrochemical preparation of high-performance PEDOT.

PEDOT-Based Conducting Polymer Actuators

Conducting polymers, particularly poly(3,4-ethylenedioxythiophene) (PEDOT) and its complex with poly(styrene sulfonate) (PEDOT:PSS), provide a promising materials platform to develop soft actuators or artificial muscles. To date, PEDOT-based actuators are available in the field of bionics, biomedicine, smart textiles, microactuators, and other functional applications. Compared to other conducting polymers, PEDOT provides higher conductivity and chemical stability, lower density and operating voltages, and the dispersion of PEDOT with PSS further enriches performances in solubility, hydrophility, processability, and flexibility, making them advantageous in actuator-based applications. However, the actuators fabricated by PEDOT-based materials are still in their infancy, with many unknowns and challenges that require more comprehensive understanding for their current and future development. This review is aimed at providing a comprehensive understanding of the actuation mechanisms, performance evaluation criteria, processing technologies and configurations, and the most recent progress of materials development and applications. Lastly, we also elaborate on future opportunities for improving and exploiting PEDOT-based actuators.

Electrosynthesis and electrochemical capacitive behavior of a new nitrogen PEDOT analogue-based polymer electrode

As a supercapacitor electrode, a new nitrogen PEDOT analogue (PMDTO) exhibited some outstanding electrochemical performances but still suffered some drawbacks.

Solvent effects on electrosynthesis, morphological and electrochromic properties of a nitrogen analog of PEDOT

A new nitrogen analog of 3,4-ethylenedioxythiophene (EDOT), N-methyl-3,4-dihydrothieno[3,4-b][1,4]oxazine (MDTO), was electropolymerized in different solvents (deionized water, acetonitrile, and propylene carbonate) using LiClO4 as the electrolyte. The structure and performance of as-prepared PMDTO polymers were systematically studied by cyclic voltammetry, UV-vis spectroscopy, FT-IR, SEM, thermogravimetry, spectroelectrochemistry and electrochromic techniques. To our surprise, solvents had a major influence on the electropolymerization of MDTO and properties of the resultant polymers, including morphology, electrochemistry, electronic and optical properties, and electrochromics, etc. In aqueous solution, MDTO revealed the lowest onset oxidation potential (0.19 V) than in acetonitrile (0.48 V) and propylene carbonate (0.49 V). However, PMDTO films showed rather poor cycling stability in water, while outstanding stability in acetonitrile and propylene carbonate. Films prepared in propylene carbonate displayed a rather smooth morphology, lower band gap (1.65 eV), higher transparency (97.3%) and a contrast ratio (44.6%) at λ = 466 nm. PMDTO films obtained in acetonitrile showed significantly higher coloration efficiency (169.5 cm(2) C(-1)) than in other two solvents (∼ 97.6 cm(2) C(-1)) with a moderate contrast ratio (24.5%).