An Evaluation of the Effectiveness of a Charged Bilayered Conducting Fine Mesh as a Dust Filter

Aim: To develop a mesh meant to be mounted on a windowpane that will act as a barrier for dust, while allowing wind to pass freely. Materials and Methods: Two small metal meshes separated at 1 cm, connected to an electrostatic generator and holding opposite charges are used. A videographic analysis has been performed. Results: The charged bilayered mesh was able to prevent a large portion of dust from passing through. Conclusion: The device is a simple, economical, and reliable way of reducing the entry of dust into a room, easing the need for periodic cleaning, and thus creating a healthier environment for the inhabitants of the building. It also has potential space applications.

Attenuating microwave radiation by absorption through controlled nanoparticle localization in PC/PVDF blends

Nanoscale ordering in a polymer blend structure is indispensable to obtain materials with tailored properties. It was established here that controlling the arrangement of nanoparticles, with different characteristics, in co-continuous PC/PVDF (polycarbonate/poly(vinylidene fluoride)) blends can result in outstanding microwave absorption (ca. 90%). An excellent reflection loss (RL) of ca. -71 dB was obtained for a model blend structure wherein the conducting (multiwall carbon nanotubes, MWNTs) and the magnetic inclusions (Fe3O4) are localized in PVDF and the dielectric inclusion (barium titanate, BT) is in PC. The MWNTs were modified using polyaniline, which facilitates better charge transport in the blends. Furthermore, by introducing surface active groups on BT nanoparticles and changing the macroscopic processing conditions, the localization of BT nanoparticles can be tailored, otherwise BT nanoparticles would localize in the preferred phase (PVDF). In this study, we have shown that by ordered arrangement of nanoparticles, the incoming EM radiation can be attenuated. For instance, when PANI-MWNTs were localized in PVDF, the shielding was mainly through reflection. Now by localizing the conducting inclusion and the magnetic lossy materials in PVDF and the dielectric materials in PC, an outstanding shielding effectiveness of ca. -37 dB was achieved where shielding was mainly through absorption (ca. 90%). Thus, this study clearly demonstrates that lightweight microwave absorbers can be designed using polymer blends as a tool.

A 1 V supercapacitor device with nanostructured graphene oxide/polyaniline composite materials

Polyaniline and graphene oxide composite on activated carbon cum reduced graphene oxide-supported supercapacitor electrodes are fabricated and electrochemically characterized in a three-electrode cell assembly. Attractive supercapacitor performance, namely high-power capability and cycling stability for graphene oxide/polyaniline composite, is observed owing to the layered and porous-polymeric-structured electrodes. Based on the materials characterization data in a three-electrode cell assembly, 1 V supercapacitor devices are developed and performance tested. A comparative study has also been conducted for polyaniline and graphene oxide/polyaniline composite-based 1 V supercapacitors for comprehending the synergic effect of graphene oxide and polyaniline. Graphene oxide/polyaniline composite-based capacitor that exhibits about 100 F g(-1) specific capacitance with faradaic efficiency in excess of 90% has its energy and power density values of 14 Wh kg(-1) and 72 kW kg(-1), respectively. Cycle-life data for over 1000 cycles reflect 10% capacitance degradation for graphene oxide/polyaniline composite supercapacitor.

Amine Functionalized polyaniline grafted to exfoliated graphite oxide: Synthesis, characterization and multi-element sensor studies

An amine functionalized polyaniline (AMPANI) derivative has been grafted onto exfoliated graphite oxide (EGO). The synthesis involved the in-situ chemical oxidative polymerization of functionalized aniline monomer in the presence of EGO with diaminobenzene acting as a bridging ligand to yield EGAMPANI. The synthesized compound was characterized by FT-IR and FT-Raman spectroscopy as well as thermogravimetric and X-ray diffraction analysis. The EGAMPANI was then used to modify a carbon paste electrode (CPE), which was applied for multi-elemental sensing of Pb2+, Cd2+ and Hg2+ ions using differential pulse anodic stripping voltammetty. The limits of detection achieved using the EGAMPANI modified CPE were 22 x 10(-6) M for Hg2+ ion, 1.2 x 10(-6) M for Cd2+ ion and 9.8 x 10(-7) M for Pb2+ ion. (C) 2015 Elsevier B.V. All rights reserved.

Electrically conducting palladium selenide (Pd4Se, Pd17Se15, Pd7Se4) phases: synthesis and activity towards hydrogen evolution reaction

Electrically conducting, continuous films of different phases of palladium selenides are synthesized by the thermolysis of single source molecular precursors. The films are found to be adherent on flat substrates such as glass, indium tin oxide and glassy carbon and are stable under electrochemical conditions. They are electrocatalytically active and in particular, for hydrogen evolution reaction. Catalytic activities with low Tafel slopes of 50-60 mV per decade are observed.