Strategy for the syntheses of isolated fine silver nanoparticles and polypyrrole/silver nanocomposites on gold substrates

Sensor development of 1,2 Dichlorobenzene based on polypyrole/Cu-doped ZnO (PPY/CZO) nanocomposite embedded silver electrode and their antimicrobial studies

Cu-doped ZnO nanopowders and their composites of polypyrole (PPY)/CZO were prepared by a gel combustion method and an in-situ polymerization process, respectively. The synthesized nanocomposite are characterized by X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), FTIR, and TGA studies. Then the PPY/CZO/AgE nanocomposites were used for potential application in chemical sensing by easy and reliable I-V method, where 1,2 dichlorobenzene (1,2-DCB) is considered as a model target compound. The chemical sensor performances are exhibited the higher sensitivity, good stability, and repeatability of the sensor enhanced significantly using PPY/CZO/AgE of thin-film with conducting binders on silver electrodes (AgE; Surface area: 0.0216cm²). The calibration plot is linear over the large dynamic range (0.35nM∼3.5mM), where the sensitivity (∼2.702μAmM^-1cm^-2) and detection limit (∼0.34nM) is calculated based on signal/noise ratio (∼^3N/_S) in short response time. Finally, it is concluded that the structural and optical characteristics could be encompassed to a broad-scale in PPY/CZO/AgE composites and efficient chemical sensor applications for environmental fields. Simultaneously PPY/CZO composites was also evaluated against Gram positive bacteria Bacillus subtilis, Gram negative bacteria Escherichia coli and antibiotics (Amoxicillin) using the agar plate.

Antibacterial behavior of polypyrrole: The influence of morphology and additives incorporation

The antibacterial behavior of polypyrrole (PPy) depends on a diversity of structural parameters such as surface area, aggregation level and additives (metal nanoparticles) incorporation. This paper summarizes the influence of different preparation procedures of PPy on action of resulting antibacterial composite against Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. The bactericidal action has been assigned to morphology (size of polypyrrole nanoparticles). The electrostatic interaction established between polymer nanoparticles and bacteria provokes the bacterial cell death and returns advantages in comparison with conventional composites of polypyrrole decorated with metal nanoparticles.

A simple and an efficient strategy to synthesize multi-component nanocomposites for biosensor applications

We demonstrate that core-shell multi-component nanocomposites can be grown in situ at room temperature by a novel one-step approach without adding any reductant and stabilizer. We have presented a one-step method for the synthesis of multi-component nanocomposites in water solution, the multi-component nanocomposites could be produced directly and quickly in an in situ wet-chemical reaction. Here, Au-polypyrrole (PPy)/Prussian blue (PB) nanocomposites have been synthesized successfully under the same circumstance. With the addition of pyrrole monomers into mixture solutions, the autopolymerization of pyrrole into PPy and AuCl(4)(-) was reduced to elemental Au instantaneously as well as simultaneously. At the same time, PB produced along with elemental Au serving as a catalyst. Furthermore, we investigated the performance of Au-PPy/PB nanocomposites as amperometric sensor toward the reduction of H(2)O(2), which displayed high sensitivity, fast response and good stability. The peak current of H(2)O(2) increased linearly with the concentration of H(2)O(2) in the range from 2.5×10(-9) to 1.2×10(-6)M, and the low detection limit of 8.3×10(-10)M (S/N=3) was obtained. Therefore, this work provides a new pathway to design and fabricate novel multi-component nanocomposites, which have unique characteristics and hold great applications in the fields of sensors, electrocatalysis and others.

Preparação e caracterização elétrica de sensores de metanol à base de nanocompósitos híbridos de polipirrol/nanopartículas metálicas

Neste trabalho, compósitos híbridos metal/polímero (nanopartículas de ouro/polipirrol) foram sintetizados a partir da polimerização química do pirrol sobre a superfície de nanopartículas metálicas estabilizados por um agente surfactante (dodecil sulfato de sódio). A posterior solubilização do compósito em álcool polivinílico permitiu a obtenção de uma matriz orgânica auto-sustentável, flexível, com boa resistência mecânica e aplicável na detecção de compostos voláteis (com especial atenção ao metanol). Nessa direção, foram otimizadas as condições de preparação do compósito, no sentido de promover a detecção e quantificação do metanol em misturas com etanol, com o intuito de aplicar o dispositivo no reconhecimento de resquícios de metanol em bebidas alcoólicas. Dos sistemas analisados, a sensibilidade dos dispositivos se mostrou diretamente proporcional à constante dielétrica do volátil utilizado, indicando que interações físicas ocorrem na matriz na presença de voláteis.

A Novel Nonenzymatic Hydrogen Peroxide Sensor Based on a Polypyrrole Nanowire-Copper Nanocomposite Modified Gold Electrode

A novel nonenzymatic hydrogen peroxide (H2O2) sensor has been fabricated by dispersing copper nanoparticles onto polypyrrole (PPy) nanowires by cyclic voltammetry (CV) to form PPy-copper nanocomposites on gold electrodes. Scanning electron microscopy (SEM) was used to characterize the morphologies of the PPy nanowires and the PPy-copper nanocomposite. The reactivity of the PPy-copper nanocomposite towards H2O2 was characterized by cyclic voltammetry and chronoamperometry. Effects of applied potential, the concentrations of detection solution upon the response currents of the sensor were investigated for an optimum analytical performance. It was proved that the PPy-copper nanocomposite showed excellent catalytic activity for the reduction of hydrogen peroxide (H2O2). The sensor showed a linear response to hydrogen peroxide in the concentration range between 7.0×10-6 and 4.3×10-3 mol L-1 with a high sensitivity, and a detection limit of 2.3×10-6 mol L-1. Experiment results also showed that the sensor had good stability.