S. H. Oh, C.-W. Lee, D. Chun et al.

J. Mater. Chem. A • 2014

A metal-free and all-organic redox flow battery is proposed and investigated. It employs polythiophene microparticles dispersed in electrolyte solutions as the redox couple and does not depend on limited metal resources. It shows a high cell potential and stable charge/discharge performance with a high energy efficiency of 60.9%.

Estefanía Baigorria, J. Durantini, S. R. Martínez et al.

ACS Applied Bio Materials • 2021

The spreading of different infections can occur through direct contact with glass surfaces in commonly used areas. Incorporating the use of alternative therapies in these materials seems essential to reduce and also avoid bacterial resistance. In this work, the capability to kill microbes of glass surfaces coated with two electroactive metalated phthalocyanines (ZnPc-EDOT and CuPc-EDOT) is assessed. The results show that both of these materials are capable of producing reactive oxygen species; however, the polymer with Zn(II) (ZnPc-PEDOT) has a singlet oxygen quantum yield 8-fold higher than that of the Cu(II) containing analogue. This was reflected in the in vitro experiments where the effectiveness of the surfaces was tested in bacterial suspensions, monitoring single microbe inactivation upon attachment to the polymers, and eliminating mature biofilms. Furthermore, we evaluated the use of an inorganic salt (KI) to potentiate the photodynamic inactivation mediated by an electropolymerized surface. The addition of the salt improved the efficiency of phototherapy at least two times for both polymers; nevertheless, the material coated with ZnPc-PEDOT was the only one capable of eliminating >99.98% of the initial microbes loading under different circumstances.

Daniel Martín‐Yerga, E. C. Rama, A. C. Garcia

Journal of Chemical Education • 2016

A lab appropriate to introduce voltammetric techniques and basic electrochemical parameters is described in this work. It is suitable to study theoretical concepts of electrochemistry in an applied way for analytical undergraduate courses. Two electroactive species, hexaammineruthenium and dopamine, are used as simple redox systems. Screen-printed electrodes are used in order to allow the students to focus on the electrochemistry and avoid tedious instrumentation preparation. The analytical determination of the species studied with sensitive techniques such as differential-pulse or square-wave voltammetry is also performed.

Takuya Okazaki, Tatsuya Orii, Shin-Yinn Tan et al.

Analytical Chemistry • 2020

We present an electrochemical long period fiber grating (LPFG) sensor for electroactive species with an optically transparent electrode. The sensor was fabricated by coating indium tin oxide onto the surface of LPFG using a polygonal barrel-sputtering method. LPFG was produced by an electric arc-induced technique. The sensing is based on change in the detec-tion of electron density on the electrode surface during potential application and its reduction by electrochemical redox of analytes. Four typical electroactive species of methylene blue, hexaammineruthenium(III), ferrocyanide and ferrocenedi-methanol were used to investigate the sensor performance. The concentrations of analytes were determined by the modula-tion of the potential as the change in transmittance around the resonance band of LPFG. The sensitivity of the sensor, par-ticularly to methylene blue, was high, and the sensor responded to a wide concentration range of 0.001 mM to 1 mM.

Lucila Martinez Ostormujof, Sébastien Teychené, Wafa Achouak et al.

ChemElectroChem • 2023

<jats:title>Abstract</jats:title><jats:p>The decrease in the electrochemical activity of multi‐species microbial anodes in bioelectrochemical systems is the main bottleneck to overcome for bringing these technologies one‐step closer to the industrialization stage. In this study, microsized stainless steel electrodes were implemented to investigate the distinctive electrochemical behavior of salt marsh electroactive biofilms (EABs). Four main temporal stages of biocolonization and electrochemical activity were thoroughly described. Maximum biofilm growth rate, high viability and high extracellular protein matrix content favored the increasing electrochemical activity of the EAB up to its maximum current peak. Then, when gradual fall in current became irreversible, biofilm growth rate decreased together with dead cells accumulation and an increase for extracellular polysaccharides. In addition, analyses of microbial populations showed a shift from <jats:italic>Marinobacterium</jats:italic> spp. to <jats:italic>Desulfuromonas</jats:italic> spp. These findings suggest a chemical and microbial temporal evolution of the EAB, which can be directly correlated to the electrochemical performance of the bioanode.</jats:p>

Nicolò Dossi, Rosanna Toniolo, Fabio Terzi et al.

ELECTROPHORESIS • 2015

<jats:p>We propose here simple electrochemical cells assembled with electrodes pencil drawn on paper for conducting one‐spot tests enabling olive oil to be easily distinguished from other vegetable oils. They consist of small circular pads of hydrophilic paper defined by hydrophobic barriers, these last printed by using custom‐designed rubber stamps, where working, reference, and counterelectrodes are drawn by pencil leads. These cells were first wetted with a small volume of aqueous electrolyte, avoiding coating of the upper surface of electrodes. A controlled volume of edible oil samples was then applied on top of the moist cell. The results found proved that these devices can be adopted as effective platforms suitable for the detection of electroactive compounds present in edible oils. In fact, they allow voltammetric profiles to be recorded not only for the oxidation of water soluble species (ortho‐diphenols, as well as some monophenols and polyphenols) present in olive oils, but also for electroactive hydrophobic components (e.g., α‐tocopherol) present in sunflower oils, which were chosen as model of seed oils. The whole of collected findings pointed out that simple one‐spot tests performed by these devices enable olive oils to be easily distinguished from other edible oils on the basis of their clearly different voltammetric profiles. A satisfactory interdevice reproducibility (±13%) was estimated by applying strictly similar extra virgin olive oil samples onto seven different cells carefully prepared by the same procedure. An operating mechanism able to account for the detection of also electroactive hydrophobic compounds present in oils is proposed.</jats:p>

Dulan B. Gunasekara, Manjula B. Wijesinghe, Pann Pichetsurnthorn et al.

The Analyst • 0

<p>Dual-channel/dual-parallel electrode configuration for microchip electrophoresis with electrochemical detection for voltammetric characterization of electrochemically active analytes in biological samples.</p>

Alexander Oleinick, Yun Yu, Michael V. Mirkin et al.

ChemElectroChem • 2019

<jats:title>Abstract</jats:title><jats:p>The electron transfer/ion transfer mode of scanning electrochemical microscopy (SECM), in which a nanopipette containing a solvent immiscible with the outer solution is used as a tip to approach a microelectrode substrate, is investigated by simulations in order to analyze the effect of the electroactive species being simultaneously present inside the nanopipette and in the external liquid phase. The simulations consider conventional transport modes of the species inside the nanopipette as well as in the bulk solution coupled with their transfer across the liquid‐liquid nanointerface supported at the nanopipette tip. The shapes of the simulated approach curves (tip current vs. tip‐substrate distance) are highly sensitive to the ratio of initial concentrations in the nanopipette and in the outer solution for a given partition coefficient value providing a direct method to determine its value. The effect of the 1<jats:sup>st</jats:sup> and 2<jats:sup>nd</jats:sup> order homogeneous reaction consuming the product electrogenerated at the microelectrode surface onto its collection by the nanopipette is also presented.</jats:p>

Sabine Szunerits, Patrick Garrigue, Jean‐Luc Bruneel et al.

Electroanalysis • 2003

<jats:title>Abstract</jats:title><jats:p>The fabrication of an ordered electrode array based on an etched optical fiber bundle is described. The high density sub‐micrometer electrode array is characterized electrochemically using cyclic voltammetry and geometrically via scanning electron microscopy. The observed steady‐state current indicates that individual diffusion layers do not overlap and that the electrodes are diffusively independent. Spatially resolved chemical information of the etched and insulating paint‐covered surface of the electrode array is obtained from confocal Raman microspectroscopy (CRM) experiments. Finally electroactive spots are probed using CRM through the different Raman spectra of the electroactive species of the redox couple Fe(CN)<jats:sub>6</jats:sub><jats:sup>3−</jats:sup>/Fe(CN)<jats:sub>6</jats:sub><jats:sup>4−</jats:sup>.</jats:p>

Parbury P. Schmidt, Harry B. Mark

The Journal of Chemical Physics • 1965

<jats:p>It is assumed in this paper that at the electrode—solution interface there is molecular order of the electroactive species resembling solid-state order. Specifically, it is assumed that next to the electrode is a layer of adsorbed neutral solvent molecules which are also ligands coordinated to the ions found in the interface. The mechanism of electron transfer from the electrode to the ion or the reverse from the ion to the electrode is assumed initially to involve a transition from either the electrode or the ion to the solvent molecule. This is followed by a transition of the electron from the solvent molecule to either the ion or the electrode. The two transitions involved in the net transfer of an electron across the interface are considered analogous to the charge-transfer mechanism of spectroscopy. The wavefunctions representing the system at the interface are then of the same form as the charge-transfer wavefunctions given by Mulliken.</jats:p> <jats:p>By considering the radiationless transition probabilities for the electron transitions in the interface system at the electrode, it is found that the usual current expressions result. By imposing the condition of zero net current at equilibrium the Nernst equation results. By further considering the polarization of the electrode under nonequilibrium conditions as a perturbation of the energy levels of the system, it is found that with the proper identification of terms the current expression for the polarized electrode results.</jats:p>

Paniz Izadi, Uwe Schröder

ChemElectroChem • 2022

<jats:title>Abstract</jats:title><jats:p><jats:italic>Desulfarculus baarsii</jats:italic> and <jats:italic>Desulfurivibrio alkaliphilus</jats:italic> are strictly anaerobic bacteria existing in marine sediments. <jats:italic>D. baarsii</jats:italic> gains energy through reducing sulphate and <jats:italic>D. alkaliphilus</jats:italic> is able to reduce elemental sulphur, thiosulphate and polysulphide in seawater. Both organisms were previously identified as key organisms in sediment derived, bidirectional electroactive biofilms. Here, we investigated the electrochemical performance of these two bacteria in bio‐electrochemical systems and their possible involvement in anodic and cathodic reactions. The results show that <jats:italic>D. baarsii</jats:italic> was unable to donate or accept electrons to/from an electrode, while <jats:italic>D. alkaliphilus</jats:italic> was able to catalyse both anodic and cathodic reactions and interact with the electrode through direct or potentially indirect electron transfer. Raman spectra of <jats:italic>D. alkaliphilus</jats:italic> electrode biofilms showed a high similarity to <jats:italic>Geobacter sulfurreducens</jats:italic> biofilms, including the specific bands of cytochromes b and c, explaining the electroactivity of <jats:italic>D. alkaliphilus</jats:italic> in bioelectrochemical reactions.</jats:p>

Dmitry Konev, Olga Istakova, Mikhail Vorotyntsev

Membranes • 0

<jats:p>A novel method has been proposed for rapid determination of principal transmembrane transport parameters for solute electroactive co-ions/molecules, in relation to the crossover problem in power sources. It is based on direct measurements of current for the electrode, separated from solution by an ion-exchange membrane, under voltammetric and chronoamperometric regimes. An electroactive reagent is initially distributed within the membrane/solution space under equilibrium. Then, potential change induces its transformation into the product at the electrode under the diffusion-limited regime. For the chronoamperometric experiment, the electrode potential steps backward after the current stabilization, thus inducing an opposite redox transformation. Novel analytical solutions for nonstationary concentrations and current have been derived for such two-stage regime. The comparison of theoretical predictions with experimental data for the Br2/Br− redox couple (where only Br− is initially present) has provided the diffusion coefficients of the Br− and Br2 species inside the membrane, D(Br−) = (2.98 ± 0.27) 10−6 cm2/s and D(Br2) = (1.10 ± 0.07) 10−6 cm2/s, and the distribution coefficient of the Br− species at the membrane/solution boundary, K(Br−) = 0.190 ± 0.005, for various HBr additions (0.125–0.75 M) to aqueous 2 M H2SO4 solution. This possibility to determine transport characteristics of two electroactive species, the initial solute component and its redox product, within a single experiment, represents a unique feature of this study.</jats:p>

Serge Cosnier, Rodica E. Ionescu, Michel Keddam et al.

Electroanalysis • 2008

<jats:title>Abstract</jats:title><jats:p>The carbon cavity microelectrode (CME), exhibiting a volume of 4×10<jats:sup>−6</jats:sup> cm<jats:sup>3</jats:sup>, offers a genuine alternative for immobilizing and connecting enzymes in aqueous electrolytes by powder of insoluble redox materials. In the present work, the electrochemical behavior of two redox species such as ferrocene (Fc) and tetrathiafulvalene (TTF) was investigated with CME to evaluate their potentialities in the electrical wiring of enzymes. For this purpose, powder of two enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP), was independently mixed with an insoluble redox material and forced to fill the single micro cavity of a carbon electrode covered by an inert insulator. The presence of the electroactive species, as well as the enzyme wiring was investigated by cyclic voltammetry. The amperometric detection of glucose was carried out by potentiostating the TTF/GOx and the Fc/GOx microelectrodes at 0.25 and 0.35 V respectively. The amperometric detection of H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> by the TTF/HRP microelectrode was performed at −0.1 V vs. SCE.</jats:p>

Larry R. Gibson, Sean P. Branagan, Paul W. Bohn

Small • 2013

<jats:title>Abstract</jats:title><jats:p>Significant technological drivers motivate interest in the use of reaction sites embedded within nanometer‐scale channels, and an important class of these structures is realized by an embedded annular nanoband electrode (EANE) in a cylindrical nanochannel. In this structure, the convective delivery of electroactive species to the nanoelectrode is tightly coupled to the electrochemical overpotential via electroosmotic flow. Simulation results indicate that EANE arrays significantly outperform comparable microband electrode/microchannel structures, producing higher conversion efficiencies at low Peclet number. The results of this in‐depth analysis are useful in assessing possible implementation of the EANE geometry for a wide range of electrochemical targets within microscale total analysis systems.</jats:p>

Huafang Zhou, Guangli Che, Shaojun Dong

Electroanalysis • 1997

<jats:title>Abstract</jats:title><jats:p>The mass transport dynamics of ferrocene in polyelectrolyte polyethylene glycol lithium perchlorate (PEG · LiClO<jats:sub>4</jats:sub>) was studied by using chronoamperometry at a microdisk electrode. Chronoamperometry is a powerful method for the study of mass transport in polyelectrolyte, it has many advantages over the conventional methods at a microelectrode and the steady‐state method at an ultramicroelectrode. By using this method the apparent diffusion coefficient <jats:italic>D</jats:italic><jats:sub>app</jats:sub> and concentration <jats:italic>C</jats:italic><jats:sub>a</jats:sub> of the electroactive species, can be estimated from a single experiment without previous knowledge of either one. We have estimated <jats:italic>D</jats:italic><jats:sub>app</jats:sub> and <jats:italic>C</jats:italic><jats:sub>a</jats:sub> of ferrocene in PEG · LiClO<jats:sub>4</jats:sub> polyelectrolyte from 25°C to 75°C. The dependence on the concentration of electroactive species was observed. The diffusion coefficients decrease with increasing ferrocene concentration and decreasing temperature. The mass transport mechanism is explained by using a free volume model.</jats:p>

Christoph J. Bondue, Marius Spallek, Lennart Sobota et al.

ChemSusChem • 2023

<jats:title>Abstract</jats:title><jats:p>To date the electroactive species of selective aldehyde oxidation to carboxylates at gold electrodes is usually assumed to be the diolate. It forms with high concentration only in very alkaline electrolytes, when OH<jats:sup>−</jats:sup> binds to the carbonyl carbon atom. Accordingly, the electrochemical upgrading of biomass‐derived aldehydes to carboxylates is believed to be limited to very alkaline electrolytes at many electrode materials. However, OH<jats:sup>−</jats:sup>‐induced aldehyde decomposition in these electrolytes prevents application of electrochemical aldehyde oxidation for the sustainable upgrading of biomass to value‐added chemicals at industrial scale. Here, we demonstrate the successful oxidation of aliphatic aldehydes at a rotating gold electrode at pH 12, where only 1 % of the aldehyde resides as the diolate species. This concentration is too small to account for the observed current, which shows that also other aldehyde species (i. e., the geminal diol and the non‐hydrated aldehyde) are electroactive. This insight allows developing strategies to omit aldehyde decomposition while achieving high current densities for the selective aldehyde oxidation, making its future industrial application viable.</jats:p>

Ilana Fried

Israel Journal of Chemistry • 1969

<jats:title>Abstract</jats:title><jats:p>Rigorous mathematical treatment of the classical theory of diffusion of an electroactive species to an electrode exposes an error in the theory. According to the corrected theory, the initial concentration (at t = 0) of the electroactive species is uniform throughout the solution except at the electrode surface. Fortunately, diffusion theory results remain unaltered. Two important conclusions result from the corrected theory: a. the plane of the “electrode surface” is inside the diffuse double layer, and b. the exact function of the concentration of the electroactive species in the double layer has no effect on the solution of the diffusion equation. These results, although intuitively accepted, are rigorously proved.</jats:p>

P. Jenčušová, P. Tomčík, D. Bustin et al.

Chemical Papers • 2006

<jats:title>Abstract</jats:title><jats:p>The possibility of calibrationless chronoamperometric determination is described using a pair of individually addressable and diffusion layers interacting segments of interdigitated microelectrode array (IDA). It utilizes dual voltammetric mode where the first segment is polarized with potential corresponding to the limiting current of determined species electrode reaction and the second segment is polarized with potential corresponding to the opposite electrode reaction limiting current. Time at which the current of the collector segment reaches one half of the steady state is hyperbolically dependent on the diffusion coefficient of analyte. The determination of diffusion coefficient allows direct calculation of bulk concentration avoiding calibration with a standard solution. The equipment for measuring of fast response of IDA arrays in dual mode has been developed using a bipotentiostat connected with A/D transducer. It allows less than 1 ms sampling period for ultrafast registration of chronoamperogram. The method was tested and validated with [Fe(CN)6]4−, [Ru(NH3)6]Cl3, and ferrocene model samples using various types of IDA arrays.</jats:p>

Nazario Martin

ECS Meeting Abstracts • 2015

<jats:p>The readily available and highly versatile electron donor exTTF molecule has proved its efficiency for the design of unprecedented receptors for fullerenes and other carbon nanoforms. In this regard, custom-made tweezers and macrocyclic receptors are proving a valuable alternative to achieve the affinity and selectivity required to meet goals such as the selective extraction of higher fullerenes, their chiral resolution or the self-assembly of functional molecular materials.<jats:sup>[1]</jats:sup> In this presentation some important breakthroughs based on electroactive systems derived from exTTF as molecular and macrocyclic receptors for single wall carbon nanotubes will be highlighted. Bowl and belt-shaped CNTs receptors based on this concave-convex complementarity principle will also be presented.<jats:sup>[2]</jats:sup> The recognition motives have been applied with the aim of  modifying their electronic properties,<jats:sup>[3]</jats:sup> as well as for the hierarchical organization of mesoscopic 3D helical fibers.<jats:sup> <jats:sup>[4]</jats:sup> </jats:sup> </jats:p> <jats:p> <jats:bold>References:</jats:bold> </jats:p> <jats:p>[1] a) E. M. Pérez, L. Sánchez, G. Fernández, N. Martín, <jats:italic>J. Am. </jats:italic> <jats:italic>Chem. Soc</jats:italic>., <jats:bold>2006</jats:bold>, <jats:italic>128</jats:italic>, 7172-7173; b) E. M. Pérez, N. Martín, <jats:italic>Chem. Soc. Rev</jats:italic>., <jats:bold>2008</jats:bold>, <jats:italic>37</jats:italic>, 1512-1519; c) D. Canevet, E. M. Pérez, N. Martín, <jats:italic>Angew. Chem. Int. Ed</jats:italic>. <jats:bold>2011</jats:bold>, <jats:italic>50</jats:italic>, 9248 – 9259. </jats:p> <jats:p>[2] a) M. Gallego, J. Calbo, J. Aragó, R. M. Krick Calderon, F. H. Liquido, T. Iwamoto, A. K. Greene, E. A. Jackson, E. M. Pérez, E. Ortí, D. M. Guldi, L. T. Scott, N. Martín <jats:italic>Angew. </jats:italic> <jats:italic>Chem. Int. Ed</jats:italic>., <jats:bold>2014</jats:bold>, <jats:italic>53</jats:italic>, 2170-2175; b)  A. de Juan, Y. Pouillon, L. Ruiz-González, A. Torres-Pardo, S. Casado, N. Martín, Á. Rubio, E. M. Pérez <jats:italic>Angew. </jats:italic> <jats:italic>Chem. Int. Ed.,</jats:italic> <jats:bold>2014</jats:bold>, <jats:italic>53</jats:italic>, 5394-5400; c) H. Isla, E. M. Pérez, N. Martín, <jats:italic>Angew. Chem. Int. Ed</jats:italic>., <jats:bold>2014</jats:bold>, <jats:italic>53</jats:italic>, 5629-5633. </jats:p> <jats:p>[3] a) C. Romero.Nieto, R. García, M. A. Herranz, Ch. Ehli, M. Ruppert, A. Hirsch, D. M. Guldi, N. Martín, <jats:italic>J. Am. </jats:italic> <jats:italic>Chem. Soc</jats:italic>., <jats:bold>2012</jats:bold>, <jats:italic>134</jats:italic>, 9183−9192; b) C. Romero-Nieto, R. García, M. A. Herranz, L. Rodríguez-Pérez, M. Sánchez-Navarro, J. Rojo, N. Martín, D. M. Guldi. <jats:italic>Angew. Chem. Int. Ed</jats:italic>,<jats:bold> 2013</jats:bold>, <jats:italic>52</jats:italic>, 10216-10220.  </jats:p> <jats:p>[4] J. López-Andarias, J. L. López, C. Atienza, F. G. Brunetti, C. Romero-Nieto, D. M. Guldi, N. Martín, <jats:italic>Nat. </jats:italic> <jats:italic>Commun</jats:italic>., <jats:bold>2014</jats:bold>, DOI: 10.1038/ncomms4763.</jats:p> <jats:p/> <jats:p> <jats:inline-formula> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="797fig1.jpeg" xlink:type="simple"/> </jats:inline-formula> </jats:p> <jats:p>Figure 1</jats:p> <jats:p/>

Yoseph Bar‐Cohen

Encyclopedia of Aerospace Engineering • 0

<jats:title>Abstract</jats:title><jats:p>Most biological systems that are larger than a bacteria use muscles as their actuators. Muscles are capable of lifting large loads with short time response in the range of milliseconds but they are driven by a complex mechanism that is very difficult to mimic. Electroactive polymers (EAP) are human made actuators that most closely emulate biological muscles earning them the moniker “artificial muscles”. Initially, EAP received relatively little attention due to their limited actuation capability. In the last twenty years a series of EAP materials have emerged that respond to electrical stimulation with a significant shape change. Using these materials as actuators, various novel mechanisms and devices were already demonstrated including robot fish, miniature gripper, loudspeaker, active diaphragm, catheter steering element,, and dust‐wiper. The impressive advances in improving their actuation strain capability are attracting the attention of engineers and scientists from many different disciplines. These materials are particularly attractive to biomimetic applications allowing for producing biologically inspired intelligent inventions. Increasingly, engineers are able to develop EAP actuated mechanisms that were previously considered science fiction. This chapter reviews the state of the art, challenges, and potential applications of EAP materials to aerospace engineering.</jats:p>

Diana Narvaez, Brittany Newell

Actuators • 0

<jats:p>Electroactive polymers (EAPs) represent a versatile class of smart materials capable of converting electrical stimuli into mechanical motion and vice versa, positioning them as key components in the next generation of actuators and sensors. This review summarizes recent developments in both electronic and ionic EAPs, highlighting their activation mechanisms, material architectures, and multifunctional capabilities. Representative systems include dielectric elastomers, ferroelectric and conducting polymers, liquid crystal elastomers, and ionic gels. Advances in fabrication methods, such as additive manufacturing, nanocomposite engineering, and patternable electrode deposition, are discussed with emphasis on miniaturization, stretchability, and integration into soft systems. Applications span biomedical devices, wearable electronics, soft robotics, and environmental monitoring, with growing interest in platforms that combine actuation and sensing within a single structure. Finally, the review addresses critical challenges such as long-term material stability and scalability, and outlines future directions toward self-powered, AI-integrated, and sustainable EAP technologies.</jats:p>

Barbar J. Akle, Mike Hickner, Donald J. Leo et al.

Aerospace • 2003

<jats:p>A majority of research on ionic polymer transducers has used Nafion™ as the base material. Varying the physical and chemical properties of Nafion is difficult, which limits the understanding and development of ionic transducers. In this study we investigate a novel class of polymers called BPSH (sulfonated poly(arylene ether sulfone)s). The polymers are synthesized by the direct polymerization of sulfonated monomers. This synthetic scheme affords precise control of the amount and the location of ionic groups along the polymar backbone. These polymers differ from Nafion™ in two major ways. First, the concentration of ionic groups on a mass basis is almost double that of standard Nafion™, 1.51 meq/g for BPSH-30 versus 0.91 meq/g for Nafion™ 1100. Also, the backbone of the BPSH copolymers is much stiffer than Nafion, which affords a higher modulus material. Both of these factors, ion content and modulus, are expected to affect the performance of polymer-based actuators. Another ionomer characterized is the PATS (poly(arylene thiother sulfone)s) which is similar to BPSH. For both polymers we are varying the ionic concentration, stiffness, and water content. Those variations are fostering the understanding of operating concepts of ionic transducers, especially the correlation between ionic transducers, especially the correlation between ionic concentration and performance. Experiments on BPSH-35 demonstrate improved performance as compared to Nafion™ They provide larger strain per unit volt, larger force generated, and larger bandwidth. The novel polymers are characterized as sensors and actuators.</jats:p>

Chen Ang, Zhi Yu

Applied Physics Letters • 2005

<jats:p>The dielectric spectra of poly(vinylidene fluoride-trifluoroethylene) copolymers and poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymers are studied in a wide temperature and frequency range with electric field. It is found that the dominant relaxation process displays a peculiar characteristic—a “dielectric relaxor” behavior, rather than a “ferroelectric relaxor” behavior reported in the current literature; furthermore, we show the experimental observation that the existence of nanometer scale crystals embedded in an amorphous matrix is the base of the dielectric relaxor behavior and high electroactive performance in these polymers.</jats:p>

Chao-Chin Chang, Yu-Chun Chen, Chang-Ping Yu

Sustainable Environment Research • 0

<jats:title>Abstract</jats:title><jats:p>In bioelectrochemical wastewater treatment systems, electrochemically active bacteria (EAB) in the anode can simultaneously treat wastewater and produce electricity via extracellular electron transfer. The anode potential has been reported as one way for selecting EAB; though, conflicting results of the relationship between applied potentials and the performance and community composition of EAB have been reported. In this study, we investigated the cultivation time and applied anode potentials (+0.2, 0, −0.2, and −0.4 V vs. Ag/AgCl) on the performance of current production and the compositions of the microbial community. Our results showed that the applied potentials affected the performance of current production, but the effect was substantially reduced with cultivation time. Particularly, the current gradually increased from negative to positive values with time for the applied anode potential at −0.4 V, implying the anode biofilm shifted from accepting electrons to producing electrons. In addition, principal coordinates analysis results indicated that microbial community compositions became closer to each other after long-term enrichment. Subsequently, principal component analysis demonstrated that systems with applied potentials from +0.2, 0 to −0.2 V and at −0.4 V were, respectively, reclassified into principal component 1 (higher-energy-harvesting group) and principal component 2 (lower-energy-harvesting group), implying in addition to cultivation time, the amount of energy available for bacterial growth is another key factor that influences EAB populations. Overall, this study has demonstrated that the selected cultivation time and the particular anode potentials applied in the study determine whether the applied anode potentials would affect the community and performance of EAB.</jats:p>

Jiaxin Li, Bo Song, Chongchao Yao et al.

Nanomaterials • 0

<jats:p>Iron-based nanomaterials (NMs) are increasingly used to promote extracellular electron transfer (EET) for energy production in bioelectrochemical systems (BESs). However, the composition and roles of planktonic bacteria in the solution regulated by iron-based NMs have rarely been taken into account. Herein, the changes of the microbial community in the solution by S-doped NiFe2O4 anodes have been demonstrated and used for constructing electroactive consortia on normal carbon cloth anodes, which could achieve the same level of electricity generation as NMs-mediated biofilm, as indicated by the significantly high voltage response (0.64 V) and power density (3.5 W m−2), whereas with different microbial diversity and connections. Network analysis showed that the introduction of iron-based NMs made Geobacter positively interact with f_Rhodocyclaceae, improving the competitiveness of the consortium (Geobacter and f_Rhodocyclaceae). Additionally, planktonic bacteria regulated by S-doped anode alone cannot hinder the stimulation of Geobacter by electricity and acetate, while the assistance of lining biofilm enhanced the cooperation of sulfur-oxidizing bacteria (SOB) and fermentative bacteria (FB), thus promoting the electroactivity of microbial consortia. This study reveals the effect of S-doped NiFe2O4 NMs on the network of microbial communities in MFCs and highlights the importance of globality of microbial community, which provides a feasible solution for the safer and more economical environmental applications of NMs.</jats:p>

Maren Mieseler, Mays N Atiyeh, Hector H Hernandez et al.

Journal of Industrial Microbiology and Biotechnology • 2013

<jats:title>Abstract</jats:title> <jats:p>Biological reduction of perchlorate (ClO4−) has emerged as a promising solution for the removal of perchlorate in contaminated water and soils. In this work, we demonstrate a simple process to enrich perchlorate-reducing microbial communities separately using acetate as electron donor and the municipal aerobic membrane bioreactor sludge as inoculum. Inoculation of cathodes in microbial fuel cells (MFCs) with these enrichments, and further electrochemical enrichment at constant resistance operation of the MFCs, led to perchlorate-reducing biocathodes with peak reduction rates of 0.095 mM/day (2 mg/m2/day). Analysis of the microbial diversity of perchlorate-reducing biocathodes using PCR-DGGE revealed unique community profiles when compared to the denitrifying biocathode communities. More importantly, the total time taken for enrichment of the electroactive communities was reduced from several months reported previously in literature to less than a month in this work.</jats:p>

Bernardino Virdis, Diego Millo, Bogdan C. Donose et al.

RSC Advances • 0

<p>Electrochemically active microbial biofilms are capable to produce electric current when grown onto electrodes. This work investigates the dynamics of electron transfer inside the biofilm as well as at the biofilm/electrode interface.</p>

Yin Ye, Lu Zhang, Xiaohui Hong et al.

The ISME Journal • 2024

<jats:title>Abstract</jats:title> <jats:p>Bioelectrochemical systems (BESs) exploit electroactive biofilms (EABs) for promising applications in biosensing, wastewater treatment, energy production, and chemical biosynthesis. However, during the operation of BESs, EABs inevitably decay. Seeking approaches to rejuvenate decayed EABs is critical for the sustainability and practical application of BESs. Prophage induction has been recognized as the primary reason for EAB decay. Herein, we report that introducing a competitive species of Geobacter uraniireducens suspended prophage induction in Geobacter sulfurreducens and thereby rejuvenated the decayed G. sulfurreducens EAB. The transcriptomic profile of G. sulfurreducens demonstrated that the addition of G. uraniireducens significantly affected the expression of metabolism- and stress response system-related genes and in particular suppressed the induction of phage-related genes. Mechanistic analyses revealed that interspecies ecological competition exerted by G. uraniireducens suppressed prophage induction. Our findings not only reveal a novel strategy to rejuvenate decayed EABs, which is significant for the sustainability of BESs, but also provide new knowledge for understanding phage–host interactions from an ecological perspective, with implications for developing therapies to defend against phage attack.</jats:p>

Dao‐Bo Li, Jie Li, Dong‐Feng Liu et al.

Biotechnology and Bioengineering • 2019

<jats:title>Abstract</jats:title><jats:p>Dissimilatory metal reducer <jats:italic>Geobacter sulfurreducens</jats:italic> can mediate redox processes through extracellular electron transfer and exhibit potential‐dependent electrochemical activity in biofilm. Understanding the microbial acclimation to potential is of critical importance for developing robust electrochemically active biofilms and facilitating their environmental, geochemical, and energy applications. In this study, the metabolism and redox conduction behaviors of <jats:italic>G. sulfurreducens</jats:italic> biofilms developed at different potentials were explored. We found that electrochemical acclimation occurred at the initial hours of polarizing <jats:italic>G. sulfurreducens</jats:italic> cells to the potentials. Two mechanisms of acclimation were found, depending on the polarizing potential. In the mature biofilms, a low level of biosynthesis and a high level of catabolism were maintained at +0.2 V versus standard hydrogen electrode (SHE). The opposite results were observed at potentials higher than or equal to +0.4 V versus SHE. The potential also regulated the constitution of the electron transfer network by synthesizing more extracellular cytochrome <jats:italic>c</jats:italic> such as OmcS at 0.0 and +0.2 V and exhibited a better conductivity. These findings provide reasonable explanations for the mechanism governing the electrochemical respiration and activity in <jats:italic>G. sulfurreducens</jats:italic> biofilms.</jats:p>

Laura Katherin Chaparro Díaz, Antonio Berná, Karina Boltes

Toxics • 0

<jats:p>Bioelectrochemical processes are emerging as one of the most efficient and sustainable technologies for wastewater treatment. Their application for industrial wastewater treatment is still low due to the high toxicity and difficulty of biological treatment for industrial effluents. This is especially relevant in pharmaceutical industries, where different solvents, active pharma ingredients (APIs), extreme pH, and salinity usually form a lethal cocktail for the bacterial community in bioreactors. This work evaluates the impact of the anode architecture on the detoxification performance and analyzes, for the first time, the profile of some key bioremediation enzymes (catalase and esterase) and reactive oxygen species (ROS) during the operation of microbial electrochemical cells treating real pharmaceutical wastewater. Our results show the existence of oxidative stress and loss of cell viability in planktonic cells, while the electrogenic bacteria that form the biofilm maintain their biochemical machinery intact, as observed in the bioelectrochemical response. Monitorization of electrical current flowing in the bioelectrochemical system showed how electroactive biofilm, after a short adaptation period, started to degrade the pharma effluent. The electroactive biofilms are responsible for the detoxification of this type of industrial wastewater.</jats:p>

Jaecheul Yu, Hana Park, Younghyun Park et al.

Energies • 0

<jats:p>This study investigated the effect of initially set anodic potentials (−0.3, −0.2, −0.1 and +0.1 V) on voltage production and microbial community in electroactive biofilm reactors (EBRs) treating synthetic and domestic wastewater (WW). In phase 1, EBRs were acclimated with different anodic potentials for synthetic and domestic WW. EBR (SE4) poised with +0.1 V showed the highest maximum power density (420 mW/m2) for synthetic WW, while EBR (DE3) poised with −0.1 V showed the highest maximum power density (235 mW/m2) for domestic WW. In phase 2, the EBRs were operated with a fixed external resistance (100 Ω for synthetic WW and 500 Ω for domestic WW) after the applied potentials were stopped. The EBRs showed slightly different voltage productions depending on the WW type and the initial anodic potential, but both EBRs applied with +0.1 V for synthetic (SE4) and domestic (DE4) WW showed the highest voltage production. Principal component analysis results based on denaturing gel gradient electrophoresis band profiles showed that the microbial community was completely different depending on the WW type. Nevertheless, it was found that the microbial community of EBRs applied with a negative potential (−0.3, −0.2, and −0.1 V) seemed to shift to those of EBRs applied with a positive potential (+0.1 V) regardless of WW type. Therefore, positive anodic potential is an important operating factor in electroactive biofilm development and voltage generation for rapid start-up.</jats:p>

Yang‐Chun Yong, Yang‐Yang Yu, Xinhai Zhang et al.

Angewandte Chemie • 2014

<jats:title>Abstract</jats:title><jats:p>Low extracellular electron transfer performance is often a bottleneck in developing high‐performance bioelectrochemical systems. Herein, we show that the self‐assembly of graphene oxide and <jats:italic>Shewanella oneidensis</jats:italic> MR‐1 formed an electroactive, reduced‐graphene‐oxide‐hybridized, three‐dimensional macroporous biofilm, which enabled highly efficient bidirectional electron transfers between Shewanella and electrodes owing to high biomass incorporation and enhanced direct contact‐based extracellular electron transfer. This 3D electroactive biofilm delivered a 25‐fold increase in the outward current (oxidation current, electron flux from bacteria to electrodes) and 74‐fold increase in the inward current (reduction current, electron flux from electrodes to bacteria) over that of the naturally occurring biofilms.</jats:p>

Baoli Qin, Yu Huang, Tongxu Liu et al.

Carbon Research • 0

<jats:title>Abstract</jats:title><jats:p>Dissolved organic matter (DOM) as critical redox active soil carbon plays a crucial role in shuttling electrons between bacteria and solid electron acceptors, such as iron oxides. However, research on DOM as an electron shuttle has traditionally focused on its impact on typical iron-reducing bacteria, namely strong exoelectrogens, like <jats:italic>Geobacter</jats:italic>. Besides these strong exoelectrogens, there is a significant presence of weak exoelectrogens in the soil, but studies examining how DOM affects their survival and competitiveness are lacking. This study focused on exploring the influence of DOM on weak exoelectrogens like <jats:italic>Bacillus</jats:italic> in the soil. By utilizing soil-bioelectrochemical systems (s-BESs) to enrich soil electroactive microorganisms, it investigated the relationship between the abundance of strong and weak exoelectrogens under conditions rich in DOM and conditions lacking DOM. The results showed that in the rich DOM treatment, the abundance of <jats:italic>Geobacter</jats:italic> was relatively lower (12 ± 0.5% vs. 41 ± 3%), and there was a significant negative correlation between the abundance changes of 18 weak exoelectrogens and <jats:italic>Geobacter</jats:italic>. This suggests that DOM caused a decrease in the population of strong exoelectrogens (e.g., <jats:italic>Geobacter</jats:italic>) while simultaneously promoting the growth of weak exoelectrogens (e.g., <jats:italic>Bacillus </jats:italic>and<jats:italic> Sedimentibacter</jats:italic>). Based on this, we propose that DOM, acting as an electron shuttle, creates favorable ecological niches for the thriving and propagation of weak exoelectrogens, enhancing their competitiveness within the microbial community. This new understanding provides deeper insights into the significance of DOM electron shuttling in soil microbial ecology, and raises the question: is the role of weak exoelectrogens in soil iron cycling underestimated due to the existence of DOM?</jats:p> <jats:p><jats:bold>Graphical Abstract</jats:bold></jats:p>

Osamu Ichihashi, Tatiana A. Vishnivetskaya, Abhijeet P. Borole

ChemElectroChem • 2014

<jats:title>Abstract</jats:title><jats:p>A bioanode was optimized to generate current densities reaching 38.4±4.9 A m<jats:sup>−2</jats:sup>, which brings bioelectrochemical systems closer to commercial consideration. Glucose and lactate were fed together in a continuous or fed‐batch mode. The current density increased from 2.3 A m<jats:sup>−2</jats:sup> to 38.4 A m<jats:sup>−2</jats:sup> over a 33 day period and remained stable thereafter. The Coulombic efficiency ranged from 50 % to 80 %. A change in substrate concentration from 200 mg <jats:sc>L</jats:sc><jats:sup>−1</jats:sup> to 5 mg <jats:sc>L</jats:sc><jats:sup>−1</jats:sup> decreased maximum current density from 38.4 A m<jats:sup>−2</jats:sup> to 12.3 A m<jats:sup>−2</jats:sup>. The anode consortia included <jats:italic>Firmicutes</jats:italic> (55.0 %), <jats:italic>Proteobacteria</jats:italic> (41.8 %) and <jats:italic>Bacteroidetes</jats:italic> (2.1 %) constituting two potentially electrogenic genera: <jats:italic>Geobacter</jats:italic> (6.8 %) and <jats:italic>Aeromonas</jats:italic> (31.9 %). The current production was found to be limited by kinetics during the growth period (33 days), and mass transfer, thereafter. The results indicate the necessity of removing spent biomass for efficient long‐term operation and treatment of wastewater streams.</jats:p>

Pierre Belleville, Gerard Merlin, Julien Ramousse et al.

Scientific Reports • 0

<jats:title>Abstract</jats:title><jats:p>Activity distribution limitation in electroactive biofilm remains an unclear phenomenon. Some observations using confocal microscopy have shown notable difference between activity close to the anode and activity at the liquid interface. A numerical model is developed in this work to describe biofilm growth and local biomass segregation in electroactive biofilm. Under our model hypothesis, metabolic activity distribution in the biofilm results from the competition between two limiting factors: acetate diffusion and electronic conduction in the biofilm. Influence of inactive biomass fraction (i.e. non-growing biomass fraction) properties (such as conductivity and density) is simulated to show variation in local biomass distribution. Introducing a dependence of effective diffusion to local density leads to a drastic biomass fraction segregation. Increasing density of inactive fraction reduces significantly acetate diffusion in biofilm, enhances biomass activity on the outer layer (liquid/biofilm interface) and maintains inner core largely inactive. High inactive fraction conductivity enhances biomass activity in the outer layer and enhances current production. Hence, investment in extracellular polymer substance (EPS), anchoring redox components, is benefit for biofilm electroactivity. However, under our model hypothesis it means that conductivity should be two order lower than biofilm conductivity reported in order to observe inner core active biomass segregation.</jats:p>

Carlos A. Ramírez-Vargas, Carlos A. Arias, Liang Zhang et al.

• 0

<jats:p>Abstract. The performance enhancement of constructed wetlands can be achieved through the coupling with microbial electrochemical technologies (MET). MET is a setup designed to mimic metabolic electrons exchange with insoluble donors and acceptors with the aid of electroactive bacteria and external electrical circuits. An alternative MET that dispenses of electrodes and circuits but uses an electro-conductive biofilter is called Microbial Electrochemical-based Constructed Wetland (METland). Previously it has been demonstrated that a METland has higher biodegradation rates than horizontal flow constructed wetlands, however given its novelty there are still uncertainties related to the removal of pollutants, including their microbial activity. The genetic characterization of microbial communities of a METland is desirable, but is time and resource consuming, then a characterization alternative could be based on functional analysis of the microbial communities. Community-level physiological profile (CLPP) is a useful method to evaluate the functional diversity of microbial communities based on the carbon source utilization pattern (CSUP). Therefore, this study was focused on the microbial characterization of laboratory scale METland based on CLPP analysis. The study included the characterization of microbial communities attached to two carbon-based electro-conductive materials (calcined petroleum coke from crushed electrodes – PK-A; calcined petroleum coke with low sulphur and nitrogen content – PK-LSN), in planted and non-planted set-ups. Variations on the metabolic activity of tested systems were identified and it seems to be related to the characteristics of the material, rather than the presence/absence of plants. In general, CSUP show differences along flow pathway, as well as among the tested systems, being carbohydrates and carboxylic/acetic acids the most consumed carbon sources, followed by polymers, amides/amines and amino acids. Also, were established some correlations between the utilization of carbon sources and the removal of pollutants. The obtained results provide useful insight into the spatial dynamics of METland systems. </jats:p>

Valentina Domenici, Blaž Župančič, Maja Remškar et al.

Advances in Science and Technology • 0

<jats:p>The insertion of inorganic nanoparticles and nanowires in a liquid crystalline elastomeric environment is here investigated. The combination of ferroelectric and conductive properties of the nanomaterials with the thermo-mechanical and shape memory response of liquid single crystal elastomers based on polysiloxane is indeed very promising for new technological applications, such as electroactive actuators. In this work the preparation and physical-chemical properties of new composites are presented and discussed in comparison with those of standard liquid single crystal elastomers (LSCEs). In particular, we are reporting the preliminary results of new composites including either lead titanate nanoparticles or molibdene oxide nanowires, having different electric and conductive properties.</jats:p>

Saniyat Kurbanalieva, Vyacheslav Arlyapov, Anna Kharkova et al.

Sensors • 0

<jats:p>The possibility of the developing a biochemical oxygen demand (BOD) biosensor based on electroactive biofilms of activated sludge grown on the surface of a graphite-paste electrode modified with carbon nanotubes was studied. A complex of microscopic methods controlled biofilm formation: optical microscopy with phase contrast, scanning electron microscopy, and laser confocal microscopy. The features of charge transfer in the obtained electroactive biofilms were studied using the methods of cyclic voltammetry and electrochemical impedance spectroscopy. The rate constant of the interaction of microorganisms with the extracellular electron carrier (0.79 ± 0.03 dm3(g s)−1) and the heterogeneous rate constant of electron transfer (0.34 ± 0.02 cm s−1) were determined using the cyclic voltammetry method. These results revealed that the modification of the carbon nanotubes’ (CNT) electrode surface makes it possible to create electroactive biofilms. An analysis of the metrological and analytical characteristics of the created biosensors showed that the lower limit of the biosensor based on an electroactive biofilm of activated sludge is 0.41 mgO2/dm3, which makes it possible to analyze almost any water sample. Analysis of 12 surface water samples showed a high correlation (R2 = 0.99) with the results of the standard method for determining biochemical oxygen demand.</jats:p>

Philippe Dubois, Samuel Rosset, Muhamed Niklaus et al.

Advances in Science and Technology • 0

<jats:p>One of the key factors to obtain large displacements and high efficiency with dielectric electroactive polymer (DEAPs) actuators is to have compliant electrodes. Attempts to scale DEAPs down to the mm or micrometer range have encountered major difficulties, mostly due to the challenge of micropatterning sufficiently compliant electrodes. Simply evaporating or sputtering thin metallic films on elastomer membranes produces DEAPs whose stiffness is dominated by the metallic film. Low energy metal ion implantation for fabricating compliant electrodes in DEAPs presents several advantages: a) it is clean to work with, b) it does not add thick passive layers, and c) it can be easily patterned. We use this technology to fabricate DEAPs micro-actuators whose relative displacement is the same as for macro-scale DEAPs. With transmission electron microscope (TEM) we observed the formation of metallic clusters within the elastomer (PDMS) matrix, forming a nano-composite. We focus our studies on relating the properties of this nano-composite to the implantation parameters. We identified the optimal implantation parameters for which an implanted electrode presents an exceptional combination of high electrical conductivity and low compliance.</jats:p>

Federico Carpi, Carlo Menon, Danilo De Rossi

Advances in Science and Technology • 0

<jats:p>Technologies for space applications are often considered to be rather conservative, aimed at ensuring reliability and robustness. Nevertheless, novel concepts coming from research activities have been and are always the lymph for the development of successful and competitive new solutions. This paper presents new concepts and ideas inspired by natural systems with distributed actuation embedded in their structure, considered as ideal models for possible uses in space applications. Preliminary concepts for possible technical solutions for long-term future implementations are here proposed and briefly analyzed. Peristaltic-like actuations obtained by the use of dielectric elastomer actuators is proposed as one of the most promising solutions. Experimental performances of a single actuation unit are here presented and directions for future implementations are proposed.</jats:p>