Electrochromic and highly stable poly(3,4-ethylenedioxythiophene) switches between opaque blue-black and transparent sky blue

Polycarbazole nanocomposites with conducting metal oxides for transparent electrode applications

The preparation and characterization of conducting polycarbazole (PCz) hybrid films with a colorless transparency are described. They were prepared by the vacuum evaporation of tin, aluminum, or gallium onto anion-doped green-colored PCz films, or by applying gallium to the films, followed by their exposure to ambient air. The resultant hybrid films consisting of an undoped PCz backbone and metal compounds exhibited good transparencies (90-95% at a wavelength of 550 nm). The hybrid films have a specific cross-sectional structure in which the small regions of the metal compounds are dispersed in the PCz backbone. The hybridization reaction was mechanistically explained on the basis of the combination of a metal corrosion reaction and polymer dedoping reaction, which was successfully supported by the chemical analyses of the hybrid films. The electric conductivities of the hybrid films, measured by a four-point-probe method, ranged from 2.2 x 10(-4) to 6.0 x 10(-3) S cm(-1), which are considered to be the lowest limit because the use of the hybrid films as an electrochemical electrode reveals that a network of conductive paths is preferentially formed in the film thickness direction rather than in the in-plane direction.

Significant conductivity enhancement of conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) films through a treatment with organic carboxylic acids and inorganic acids

Significant conductivity enhancement was observed on transparent and conductive poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films after a treatment with organic and inorganic acids, including acetic acid, propionic acid, butyric acid, oxalic acid, sulfurous acid, and hydrochloric acid. The conductivity could be enhanced from 0.2 to over 200 S cm(-1), that is, by a factor of more than 1000. The conductivity enhancement was dependent on the structure of the acids and the experimental conditions during the treatment, such as the acid concentration and the temperature. The optimal temperature was in the range of 120 to 160 degrees C. The resistance dropped rapidly when a PEDOT:PSS film was treated with acid solution of high concentration, whereas it gradually increased and then decreased when it was treated with an acid solution of low concentration. The mechanism for this conductivity enhancement was studied by various chemical and physical characterizations. The temperature dependence of conductivity indicates that the energy barrier for charge hopping among the PEDOT chains become lower in the highly conductive PEDOT:PSS film after the acid treatment. The ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectroscopy, the X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) indicate the loss of polystyrene sulfonic acid (PSSH) chains from the PEDOT:PSS film after the acid treatment, and the atomic force microscopy (AFM) suggest conformational change of the polymer chains. Therefore, the conductivity enhancement is attributed to the loss of PSSH chains from the PEDOT:PSS film and the conformational change of the PEDOT chains, which are induced by the acids.

Active control of epithelial cell-density gradients grown along the channel of an organic electrochemical transistor

Complex patterning of the extracellular matrix, cells, and tissues under in situ electronic control is the aim of the technique presented here. The distribution of epithelial cells along the channel of an organic electrochemical transistor is shown to be actively controlled by the gate and drain voltages, as electrochemical gradients are formed along the transistor channel when the device is biased..

A general synthesis for PEDOT-coated nonconductive materials and PEDOT hollow particles by aqueous chemical polymerization

A method for coating functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) on nonconductive substrates in aqueous solution allows the deposition of PEDOT thin layers on various substrates, including silica and polystyrene (PS) nanoparticles, siliceous mesocellular foam, and chitosan-alginate fibers. The surface property is tuned by controlling the monomer composition in the aqueous solutions. Using appropriate organic solvents to remove the PS cores of PEDOT-coated PS nanoparticles, hollow PEDOT particles with single holes and PEDOT capsules can be formed.

Poly(3,4-ethylenedioxythiophene) (PEDOT) nanobiointerfaces: thin, ultrasmooth, and functionalized PEDOT films with in vitro and in vivo biocompatibility

Nanobiointerfaces were prepared based on an electrically conductive polyethylenedioxythiophene (PEDOT). Thin (<100 nm), ultrasmooth (roughness ( R(rms)) < 5 nm), and functionalized PEDOT films have been successfully electropolymerized using aqueous microemulsion. The microemulsion polymerization is found to be catalyzed in the presence of a low concentration of acid and allows for film formation from various functionalized ethylenedioxythiophenes (EDOTs) (e.g., EDOT-OH, C(2)-EDOT-COOH, C(4)-EDOT-COOH, C(2)-EDOT-NHS, EDOT-N(3)) and their mixtures. The nanobiointerfaces are compositionally tunable and controlled to deposit on selected electrode surfaces. They prefer orthogonal growth on patterned surfaces and are synthesized within seconds. These thin PEDOT films exhibit very low intrinsic cytotoxicity and display no inflammatory response upon implantation, making them ideal for biosensing and bioengineering applications.

Diethyl 2,3-dihydrothieno[3,4-b]-1,4-dioxine-5,7-dicarboxylate

The title compound, C₁₂H₁₄O₆S, is a dicarboxylic acid diethyl ester of 3,4-ethyl­enedioxy­thio­phene, which is a component of electrically conductive poly(3,4-ethyl­enedioxy­thio­phene) (PEDOT). The ethyl­ene group is disordered over two sites with occupancy factors 0.64 and 0.36. Both the carbonyl groups are coplanar with the thio­phene ring. The mol­ecules form centrosymmetric dimers with an R₂²(12) coupling by inter­molecular C—H⋯O hydrogen bonds [3.333 (5) Å] at the ethoxy­carbonyl groups. The dimer units are arranged to form a ribbon-like mol­ecular sheet.

Hybrid bioelectrocatalyst for hydrogen peroxide reduction: Immobilization of enzyme within organic–inorganic film of structured Prussian Blue and PEDOT

Fabrication of structured film (on glassy carbon substrate) composed of compact Prussian Blue (that has been prepared by alternate immersions and through assembling within ultra-thin layers of 4(pyrrole-1-yl)-benzoic acid, PPyBA) and poly(3,4-ethylendioxythiophene), PEDOT, is described. This functionalized film has been characterized by fast charge propagation, and it has served as a redox conducting template for permanent attachment of a model enzyme, horseradish peroxidase, HRP. The resulting organic-inorganic system acts as an effective hybrid bioelectrocatalyst for electroreduction of hydrogen peroxide, a model reactant for biosensors and biofuel cells. Among important issues are rigidity, permanence of enzyme attachment, morphology, hydrophilicity, and attractive mediating capabilities of the PEDOT-stabilized Prussian Blue based structured film.

Electronic control of Ca2+ signalling in neuronal cells using an organic electronic ion pump

Cells and tissues use finely regulated ion fluxes for their intra- and intercellular communication. Technologies providing spatial and temporal control for studies of such fluxes are however, limited. We have developed an electrophoretic ion pump made of poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS) to mediate electronic control of the ion homeostasis in neurons. Ion delivery from a source reservoir to a receiving electrolyte via a PEDOT:PSS thin-film channel was achieved by electronic addressing. Ions are delivered in high quantities at an associated on/off ratio exceeding 300. This induces physiological signalling events that can be recorded at the single-cell level. Furthermore, miniaturization of the device to a 50-microm-wide channel allows for stimulation of individual cells. As this technology platform allows for electronic control of ion signalling in individual cells with proper spatial and temporal resolution, it will be useful in further studies of communication in biological systems.