In-situ conductance measurement during electropolymerization

Kankare, Jouko; Kupila, E.-L.

doi:10.1016/0022-0728(92)80074-e

Cited by 86 publications

(65 citation statements)

References 13 publications

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“…9 and references therein). Biofilm conductivity (s) was calculated from the measured conductance (G) using conformal mapping (the Schwarz-Christoffel transformation) 34 as described previously 9 using the following relation:…”

Section: Biofilm Conductivity Calculationmentioning

confidence: 99%

Biofilm conductivity is a decisive variable for high-current-density Geobacter sulfurreducens microbial fuel cells

Malvankar

Tuominen

Lovley

2012

Energy Environ. Sci.

244

184

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Current outputs of microbial fuel cells (MFCs) are too low for most perceived practical applications. Most efforts for further optimization have focused on modifications of fuel cell architecture or electrode materials, with little investigation into the properties of microorganisms that are most essential for maximal current production. Geobacter sulfurreducens produces the highest current densities of any known pure culture; is closely related to the Geobacter species that often predominate in anode biofilms harvesting electricity from organic wastes; and produces highly conductive anode biofilms. Comparison of biofilm conductivities and current production in different strains of G. sulfurreducens revealed a direct correlation between biofilm conductivity and current density. Electrochemical impedance spectroscopy measurements demonstrated that higher biofilm conductivity not only reduced resistance to electron flow through the biofilm, but also lowered the activation energy barrier for electron transfer between the biofilm and the anode. These results demonstrate the crucial role of biofilm conductivity in achieving high current density in MFCs and suggest that increasing biofilm conductivity can boost MFC performance.

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Section: Biofilm Conductivity Calculationmentioning

confidence: 99%

Biofilm conductivity is a decisive variable for high-current-density Geobacter sulfurreducens microbial fuel cells

Malvankar

Tuominen

Lovley

2012

Energy Environ. Sci.

244

184

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“…Conformal mapping (the Schwarz-Christoffel transformation) (Kankare and Kupila, 1992) was employed to calculate sediment conductivity from measured conductance (G) according to the following formula…”

Section: Conductivity Calculationmentioning

confidence: 99%

Centimeter-long electron transport in marine sediments via conductive minerals

2014

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Centimeter-long electron conduction through marine sediments, in which electrons derived from sulfide in anoxic sediments are transported to oxygen in surficial sediments, may have an important influence on sediment geochemistry. Filamentous bacteria have been proposed to mediate the electron transport, but the filament conductivity could not be verified and other mechanisms are possible. Surprisingly, previous investigations have never actually measured the sediment conductivity or its basic physical properties. Here we report direct measurements that demonstrate centimeter-long electron flow through marine sediments, with conductivities sufficient to account for previously estimated electron fluxes. Conductivity was lost for oxidized sediments, which contrasts with the previously described increase in the conductivity of microbial biofilms upon oxidation. Adding pyrite to the sediments significantly enhanced the conductivity. These results suggest that the role of conductive minerals, which are more commonly found in sediments than centimeter-long microbial filaments, need to be considered when modeling marine sediment biogeochemistry.

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“…Consequently, conductometric/impedometric transducing is the most common transducing technique used with CP. Several configurations have been used for such measurements (Figure 12 [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The measurement can be performed at DC mode by application of constant current or voltage.…”

Section: Transducers For Artificial Receptors Based On Conducting Polmentioning

confidence: 99%

Conducting Polymers as Artificial Receptors in Chemical Sensors

Lange

Roznyatovskaya

Hao

et al. 2010

Artificial Receptors for Chemical Sensors

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Conducting polymers are commonly used materials in chemical and biological sensors. These materials possess receptor as well as transducer functions [1]. Typical examples of conducting polymers (CPs) include polythiophenes, polypyrroles, polyanilines, and polyphenylenes. Such polymers show some intrinsic receptor properties towards analytes that can react/interact with the polymer, like, for example, redox active or acidic/basic gases. Oxidation/reduction and in some cases protonation/ deprotonation introduces/removes charge carriers in the conjugated backbone, whereas conformational changes alter the planarity of the conjugated backbone, which leads to changes in the mobility of the charge carriers. Figure 12.1 demonstrates the example of PANI (polyaniline), showing the influence of redox potential and pH on the interconversion between the different forms of PANI.These changes can be detected by in situ resistance, UV-vis, IR, or fluorescence measurements. Direct interactions with the p-system often produce very large signal changes; however, they are quite non-specific. A possible way to introduce some selectivity in these polymers is to modify their conjugated backbone with receptors.Usually, receptors can be introduced into a polymer backbone either after polymerization or directly to monomer, which is polymerized or copolymerized. The synthetic availability and the ability to polymerize the monomer under certain conditions are the most common limitations in the choice of a derivative with receptor group. Some classes of these receptors are discussed in Section 12.4. Doping of CPs by counter ions bearing the required receptor [2-8], the inclusion of ionophores into the polymer matrix [9], and the chemical linkage of ligands or receptor units to the polymer backbone [10] are also applied to enhance the selectivity and sensitivity of CPs. Receptors attached to the p-system via some short side chain can communicate with the p-system of the polymer by, for example, electron donating/withdrawing, electrostatic interactions or by inducing conformational changes upon analyte binding. As there is no direct interaction with the polymer backbone, the signal change may be smaller, but also much more specific. Artificial Receptors for Chemical Sensors. Edited

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In-situ conductance measurement during electropolymerization

Cited by 86 publications

References 13 publications

Biofilm conductivity is a decisive variable for high-current-density Geobacter sulfurreducens microbial fuel cells

Biofilm conductivity is a decisive variable for high-current-density Geobacter sulfurreducens microbial fuel cells

Centimeter-long electron transport in marine sediments via conductive minerals

Conducting Polymers as Artificial Receptors in Chemical Sensors

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