Conductive Microparticles Research Articles

Construction of an Electrochemical Cell System Based on Carbon Composite Film Electrodes and its Application for Voltammetric Determination of Triclosan

AbstractAn array of carbon composite electrodes embedded in a 96 well microtitration plate was fabricated and applied for DPV determination of the environmental pollutant triclosan (5‐chloro‐2‐(2,4‐dichlorophenoxy)‐phenol). For the preparation of composite electrodes, graphite and glassy carbon conductive microparticles were tested in combination with several types of polymers as nonconductive binders. For the measurements, combinations of graphitic carbon particles with polystyrene (C‐PS) and with polycarbonate (C‐PC) were selected. The achieved limit of detection was 0.49 µmol L−1 for C‐PS electrodes and 0.25 µmol L−1 for C‐PC electrodes in the selected optimum medium. The method was successfully applied for practical samples of river water and toothpaste.

Fabrication of Conductive Microparticles as Anodal Electrode in Microfluidic Microbial Fuel Cell

Microbial fuel cell (MFC) is developed as a renewable energy source, which can simultaneously carries out wastewater treatment. The ability of microorganism in generating extractable electricity highly affects the performance of a MFC; therefore, it is critical to construct a high throughput analysis platform for microorganism screening. Microfluidic MFCs are recently developed for the rapid analysis; however, several challenges remained to be overcome to construct straightforward techniques. This study presents an innovative anode composed of conductive microparticles for encapsulating electricity-generating microbes in microfluidic MFCs. The conductive polymer microparticles (Diallyldimethylammonium chloride, DADMAC) encapsulating microorganisms were generated by a T-junction microchannel. The surface area per volume of the pDADMAC micro-particle was 2.17x106 cm-1 and it can provide extensive surface area for electron transfer. We first examined the electricity generated from these particles using a batch-type operation. Microparticles containing microbes generated open circuit voltage (OCV) of 8mV in the first hour and the OCV gradually decreased to 0mV in 6hours, indicating the depletion of substrate. Particles without microbes had relatively stable OCV around 1mV throughout the operation except for the first 10min. The conductive microparticles were also applied in an air-cathode batch-type MFC and they increased the OCV from ∼0V to ∼20mV compared with freely suspended microorganisms. These results show the great potential of utilizing the conductive microparticles as anodal electrode in microfluidic microbial fuel cells.

Modeling of Interaction Layers from Conductive Microparticles with TE Electromagnetic Wave

Dependences of distribution, penetration, reflection and absorption of microwaves in the layers of conductive micro-particles on the frequency of the incident radiation and size of particles are obtained and investigated. Layers of conductive spherical particles as the shell, and without it are accepted in our work as the most common model of powder metals. So, this study allows to describe and classify features of electromagnetic wave heating of various metal powders and to predict the performance, in which it will be effective heating of metal powders by electromagnetic radiation.

Controllable dielectric and electrical performance of polymer composites with novel core/shell-structured conductive particles through biomimetic method

Novel silica/poly(dopamine)/silver (from inner to outer) (denoted as SiO2/PDA/Ag) conductive micro-particles were first synthesized by biomimetic poly(dopamine) coating. These micro-particles were then coated with a poly(dopamine) layer to form core/shell-structured particles, with silica/poly(dopamine)/silver core and poly(dopamine) shell (denoted as SiO2/PDA/Ag/PDA). This multilayer core/shell micro-particles were confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscope. Polymer composites were then prepared by mechanical blending of poly(dimethyl siloxane) and the core/shell-structured particles. It was found that the silver layer and the poly(dopamine) shell had good adhesion with substrate and they kept intact even under violent shearing stress during mechanical mixing. The effect of the thickness of outermost poly(dopamine) shell as well as the loading amount of this filler on the dielectric and electrical properties of the composites was further studied. The results showed that the dielectric constant, dielectric loss, and conductivity of the composites decreased with increasing shell thickness (10–53nm) at the same loading level. And the maximal dielectric constant of composites was achieved in the composites filled with SiO2/PDA/Ag/PDA (with 10–15nm PDA shell) particles, which was much larger than that of the composite filled with SiO2/PDA/Ag particles without insulative PDA shell. At the same time, the composites can change from conductor into insulator by controlling the shell thickness of core/shell-structured conductive particles. This simple and controllable biomimetic method may be applied to construct many other conductive filler in order to realize controllable dielectric and electrical performance of polymer composites.

‘Pearls in paddy field’: monodisperse boron-doped diamond microspheres produced in a silica-nanosphere-layers matrix by chemical vapor deposition

Monodisperse boron-doped diamond microspheres (BDDMS) have been fabricated by hot filament chemical vapor deposition (HFCVD) technology in a silica-nanosphere-layers matrix. This novel carbon material was characterized using scanning electron microscopy (SEM) and Raman spectroscopy. The synthesis strategy provides a simple method for preparing monodisperse spherical and conductive diamond microparticles.

Use of a Commercially Available Wood‐Free Resin Pencil as Convenient Electrode for the ‘Voltammetry of Microparticles’ Technique

AbstractA wood‐free resin pencil comprised of a lead made of graphite particles dispersed in a polymeric matrix is proposed as a convenient low‐cost electrode for the ‘Voltammetry of Microparticles’ technique instead of paraffin impregnated graphite rods. The pencil electrode was successfully applied for the characterization of insulating (Prussian blue, zeolites) and conductive (silver selenide, pyrite) microparticles in various media. The voltammetric responses were comparable to, sometimes even better than, those obtained with applying other electrochemical techniques.