Poly(3,4-ethylenedioxythiophene) (PEDOT) Derivatives: Innovative Conductive Polymers for Bioelectronics

Poly(3,4-ethylenedioxythiophene)s are the conducting polymers (CP) with the biggest prospects in the field of bioelectronics due to their combination of characteristics (conductivity, stability, transparency and biocompatibility). The gold standard material is the commercially available poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS). However, in order to well connect the two fields of biology and electronics, PEDOT: PSS presents some limitations associated with its low (bio) functionality. In this review, we provide an insight into the synthesis and applications of innovative poly(ethylenedioxythiophene)-type materials for bioelectronics. First, we present a detailed analysis of the different synthetic routes to (bio) functional dioxythiophene monomer/polymer derivatives. Second, we focus on the preparation of PEDOT dispersions using different biopolymers and biomolecules as dopants and stabilizers. To finish, we review the applications of innovative PEDOT-type materials such as biocompatible conducting polymer layers, conducting hydrogels, biosensors, selective detachment of cells, scaffolds for tissue engineering, electrodes for electrophysiology, implantable electrodes, stimulation of neuronal cells or pan-bio electronics.The work was supported by EU through the projects FP7-PEOPLE-2012-ITN 316832-OLIMPIA and FP7-PEOPLE-2013-ITN 607896-OrgBio. Ana Sanchez-Sanchez is thankful for the Postdoctoral Funding for Doctoral Research Staff Improvement Grant from the Basque Government. David Mecerreyes thanks Becas de Practicas en el Extranjero "Global Training"

Design and Synthesis of Electrochromic and Highly Conductive Polymers for Flexible and Stretchable Electronics

Archival Abstract submitte

Organic electrode coatings for next-generation neural interfaces

Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes

Synthesis of poly(3,4-propylenedioxythiophene)/MnO2 composites and their applications in the adsorptive removal of methylene blue

AbstractThe poly(3,4-propylenedioxythiophene)/MnO2 composites (PProDOT/MnO2) were prepared successfully by soaking the PProDOT powders into potassium permanganate (KMnO4) solution, with the mass ratio of PProDOT and KMnO4 from 2:1 to 1:2. The structure and morphology of composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet–visible absorption spectra (UV), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscope (FE-SEM). Furthermore, PProDOT/MnO2 composites were tested as the adsorbents for removal of methylene blue (MB) from aqueous solution. The results revealed that the composites were successfully synthesized, and the thiophene sulfur was oxidized into sulfoxide by KMnO4. The highest percentage removal of MB after 30min was 91% for PProDOT/MnO2 (1:2) composite, and the percentage removal of MB was ~12mgg−1 after 60min at initial concentrations of MB dye of 5.6mgL−1 in the case of PProDOT/MnO2 (1:2) composite. Besides, the adsorption process of PProDOT/MnO2 (1:2) composite was described by pseudo-second-order and Langmuir models

CHARACTERISATION OF PEDOT AND ITS DERIVATIVES IN ELECTROCHEMICAL SENSING APPLICATIONS

The emergence of a new class of polymer, namely conducting polymers (CPs) in late 1970s, has attracted many hysicists, chemists and materials researchers to study them in depth due to the unique properties and broad applications of this material. Poly(3,4-ethylenedioxythiophene) (PEDOT) has been found to be the most chemically stable CP to date. The aim of this project was to characterise PEDOT and its derivatives for applications in ion sensing. In this work, PEDOT and its derivatives i.e. poly(3,4-propylenedioxythiophene) (PProDOT) and poly(3,3-dibenzyl-3,4-propylenedioxythiophene) (PDBPD) doped with perchlorate ( ClO-4) have been electrochemically synthesised on glassy carbon (GC) and indium-tin-oxide coated glass (ITO) electrodes in acetonitrile. PEDOTs were also prepared in aqueous solutions using perchlorate ( ClO-4) and chloride( Cl-) counterions as comparison. Scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) measurements and Raman spectroscopy have been used to characterise the physical properties of the polymer coated glassy carbon (GC) and ITO electrodes. PDBPD has shown to have the most compact morphology, roughest and least wettable surface. The electrochemical studies have shown that PEDOT has the highest capacitive current. The combination of this property and mixed electronic and ionic conductivity make the PEDOT suitable to be used as a solid contact (transducer) in all-solid-state ion-selective electrode (ASSISE). PEDOT doped with poly(sodium 4-styrenesulfonate) (PSS) was found to be superior to hyaluronic acid (HA) as a solid contact for ASS Ca2+-, K+- and Na+-selective electrodes. Measurements of Ca2+ and K+ upon plant stress using ion ion-selective microelectrodes have been demonstrated. Chiral electrodes based on electrodeposited PEDOT doped with chiral molecules (collagen, HA and hydroxypropyl cellulose) were shown to discriminate between (R)-(−)- and (S)-(+)-mandelic acid. The work carried out in this thesis has shown that PEDOT is one of the most versatile conducting polymers

Utilizing Diffusion and Temperature as a Means of Band-Gap Modulation for Conjugated Polymers

First, the effect of monomer feed ratios when two electroactive monomers diffuse towards each other as a means of modulating the band gap by creating different copolymers is presented. From two homopolymers, having a high and low energy band gap, a set of conjugated copolymers with different energy bang gaps were prepared in a single run using diffusion fundamentals. . Hence, a combination of the two monomers is used to generate solid state electrochromic devices of any color. Second, the preparation and characterization of conductive fabric using a conjugated polymer is introduced. The electrical properties, morphology, and the effect of temperature on conductive fabric resistance over a wide range of temperature were investigated. It was found that the conductive fabric had low sheet resistance with passage of high current. The material exhibited metallic behavior at a specific temperature due to the modulation in the band gap from the semiconductor to metal rang

Superhydrophobic surfaces with low and high adhesion made from mixed (hydrocarbon and fluorocarbon) 3,4-propylenedioxythiophene monomers

International audienceThis work concerns new superhydrophobic surfaces, generated by replacing long fluorocarbon chains, which bioaccumulate, with short chains whilst at the same time retaining oleophobic properties. Here, is described the synthesis of novel original 3,4-propylenedioxythiophene derivatives containing both a short fluorocarbon chain (perfluorobutyl) and a hydrocarbon chain of various lengths (ethyl, butyl and hexyl). Superhydrophobic (contact angle water > 150° ) surfaces with good oleophobic properties (60° > contact angle hexadecane > 80° ) have been obtained by electrodeposition using cyclic voltammetry. Surprisingly, the lowest hystereses and sliding angles (Lotus effect) are obtained with the shortest alkyl chains due to the presence of microstructures made of nanofibers on the surfaces, whereas, the longest alkyl chains leads to nanosheets with high adhesion (Petal effect). Such materials are potential candidates for biomedical applications

Electrochemical poly(ProDOT) dendritic DNA aptamer biosensor for signalling interferon gamma (IFN-ɣ) TB biomarker

Philosophiae Doctor - PhDTuberculosis (TB) is an infectious disease that, despite all efforts devoted towards its eradication, remains a threat to many countries including South Africa. Current diagnostic assays do offer better performance than the conventional sputum smear microscopy and tuberculin skin tests. However, these assays have been proven to be affected by various factors including the condition of an individual's immune system and vaccination history. By far, electrochemical biosensors are amongst the currently investigated techniques to address the shortcomings associated with these diagnostics

Electrochemical supercapacitors based on a novel graphene/conjugated polymer composite system

An efficient method for the preparation of a highly conducting hybrid material from graphene oxide nanosheets (GNS) and a novel conjugated polymer, poly(3,4-propylenedioxythiophene), is demonstrated. A functionalized monomer based on 3,4-propylenedioxythiophene, namely ProDOT-OH, was covalently functionalized with GNS, followed by oxidative polymerization to prepare GNS-f-PProDOT composites. The covalent functionalization process of GNS with the monomer ProDOT-OH was activated through the simple esterification reaction between the acyl chloride derivative on the nanosheets and the pendant hydroxyl group present in the monomer. Furthermore, the monomer functionalized GNS were co-polymerized with thiophene resulting in hybrid graphene nanostructures coated with highly conducting co-polymers with a room temperature electrical conductivity as high as 22.5 S cm(-1). The resulting hybrid materials were characterized using a range of analytical techniques. The specific capacitance value of the composite and the co-polymer hybrids at a scan rate of 10 mV s(-1) has been determined to be 158 and 201 F g(-1) respectively and hence particularly promising for supercapacitors.close232