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Bulk quantities of electronic conducting polymers such as polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene) exhibiting an unusual 2D nanoclip-like morphology are described. The polymers designed by using a general oxidative template assembly route are orchestrated by an insoluble complex formed between an anionic oxidant ([S.sub.2][O.sub.8.sup.2-]) and a cationic surfactant.

Nanofibers of polyanilineand oligoanilines of controlled molecular weight are prepared by using high ionic strength aqueous system that has permitted the use of [H.sub.2][O.sub.2] with no added catalysts as a mild oxidizing agent. The films of oligoanilines deposited on plastic substrates have displayed a robust and reversible chemiresistor response to N[O.sub.2] vapor at room temperature in ambient air.

A study reveals that the absolute weights of parent polyaniline bases in the pernigraniline, emeraldine, and leucoemeraldine oxidation states are measured by light scattering and the exact number of aniline repeat units determined. It is concluded that the absolute molecular weight of parent polyaniline in all three isolable oxidation states, synthesized at three different temperatures.

We report an in situ measurement of the interaction of an imidazolium-based room temperature ionic liquid with both pure silver and a graphene-over-silver electrode under an applied electrochemical potential. At a negative applied potential, overall signal intensity increased indicating enhanced ionic liquid concentration at both silver and graphene electrodes. Vibrational modes associated with the imidazolium ring exhibited greater intensity enhancements and larger peak shifts compared with the anion indicating that the cation adsorbs with the ring and alkyl chain parallel to the electrode surface for both silver and graphene. In contrast to the silver, the surface enhanced Raman spectra of the ionic liquid near graphene showed shifts in the cation peaks even at no applied potential because of the strong π-π interaction between the ionic liquid and the graphene. Furthermore, the intensity of the graphene peak decreased in the presence of ionic liquid possibly due to the interaction between the ionic liquid and graphene. These results illustrate the effectiveness of surface-enhanced Raman spectroscopy to investigate electrolyte interactions with graphene at the liquid/electrode interface. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

High electrochemical reactivity is required for various energy and sensing applications of graphene grown by chemical vapor deposition (CVD). Herein, we report that heterogeneous electron transfer can be remarkably fast at CVD-grown graphene electrodes that are fabricated without using the conventional poly(methyl methacrylate) (PMMA) for graphene transfer from a growth substrate. We use nanogap voltammetry based on scanning electrochemical microscopy to obtain very high standard rate constants k0 ≥ 25 cms-1 for ferrocenemethanol oxidation at polystyrene-supported graphene. The rate constants are at least 2-3 orders of magnitude higher than those at PMMA-transferred graphene, which demonstrates an anomalously weak dependence of electrontransfer rates on the potential. Slow kinetics at PMMAtransferred graphene is attributed to the presence of residual PMMA. This unprecedentedly high reactivity of PMMA-free CVD-grown graphene electrodes is fundamentally and practically important. [ABSTRACT FROM AUTHOR]

Rechargeable Li-ion batteries (LIBs) are currently the dominant power source for portable electronic devices and electric vehicles, and for small-scale stationary energy storage. However, one bottleneck of the anode materials for LIBs is the poor cycling performance caused by the fact that the anodes cannot maintain their integrity over several charge–discharge cycles. In this work, we demonstrate an approach to improving the cycling performance of lithium-ion battery anodes by constructing an extended 3D network of flexible redox active polyoxometalate (POM) clusters with redox active organic linkers, herein described as POMOF. This architecture enables the accommodation of large volume changes during cycling at relatively high current rates. For example, the POMOF anode exhibits a high reversible capacity of 540 mA h g−1 after 360 cycles at a current rate of 0.25C and a long cycle life at a current rate of 1.25C (＞500 cycles). [ABSTRACT FROM AUTHOR]

By creating nanoscale pores in a layer of graphene, it could be used as an effective separation membrane due to its chemical and mechanical stability, its flexibility and, most importantly, its one-atom thickness. Theoretical studies have indicated that the performance of such membranes should be superior to state-of-the-art polymer-based filtration membranes, and experimental studies have recently begun to explore their potential. Here, we show that single-layer porous graphene can be used as a desalination membrane. Nanometre-sized pores are created in a graphene monolayer using an oxygen plasma etching process, which allows the size of the pores to be tuned. The resulting membranes exhibit a salt rejection rate of nearly 100% and rapid water transport. In particular, water fluxes of up to 106 g m−2 s−1 at 40 °C were measured using pressure difference as a driving force, while water fluxes measured using osmotic pressure as a driving force did not exceed 70 g m−2 s−1 atm−1. [ABSTRACT FROM AUTHOR]

Wereport the effect of chemical and physical treatments on thestructural stability of DNA origami nanostructures. Our result showsthat DNA nanostructure maintains its shape under harsh processingconditions, including thermal annealing up to 200 °C for 10 min,immersing in a wide range of organic solvents for up to 24 h, briefexposure to alkaline aqueous solutions, and 5 min exposure to UV/O3. Our result suggests that the application window of DNA nanostructureis significantly wider than previously believed. [ABSTRACT FROM AUTHOR]

It is generally accepted that supported graphene is hydrophobic and that its water contact angle is similar to that of graphite. Here, we show that the water contact angles of freshly prepared supported graphene and graphite surfaces increase when they are exposed to ambient air. By using infrared spectroscopy and X-ray photoelectron spectroscopy we demonstrate that airborne hydrocarbons adsorb on graphitic surfaces, and that a concurrent decrease in the water contact angle occurs when these contaminants are partially removed by both thermal annealing and controlled ultraviolet-O3 treatment. Our findings indicate that graphitic surfaces are more hydrophilic than previously believed, and suggest that previously reported data on the wettability of graphitic surfaces may have been affected by unintentional hydrocarbon contamination from ambient air. [ABSTRACT FROM AUTHOR]

We describe a method to form custom-shaped inorganic oxide nanostructures by using DNA nanostructure templates. We show that a DNA nanostructure can modulate the rate of chemical vapor deposition of SiO2 and TiO2 with nanometer-scale spatial resolution. The resulting oxide nanostructure inherits its shape from the DNA template. This method generates both positive-tone and negative-tone patterns on a wide range of substrates and is compatible with conventional silicon nanofabrication processes. Our result opens the door to the use of DNA nanostructures as general-purpose templates for high-resolution nanofabrication. [ABSTRACT FROM AUTHOR]

The electronic sensing capabilities of parachute fabrics and suspension lines coated with conducting polymers, single-walled carbon nanotubes, and their composites are described. A new synthetic method is described to obtain a thin, strongly adhering coating of conducting polymers on commercial parachute fabrics and suspension lines using oligoanilines as an undercoating. The results indicate that both materials have a sensing ability; however, the coated suspension lines show superior performance compared to the coated parachute fabrics. [ABSTRACT FROM PUBLISHER]

We demonstrate a new approach to pattern transfer for bottom-up nanofabrication. We show that DNA promotes/inhibits the etching of SiO2 at the single-molecule level, resulting in negative/positive tone pattern transfers from DNA to the SiO2 substrate. [ABSTRACT FROM AUTHOR]

Abstract: We describe a flexible, lightweight, reversible NO2 vapor sensor based on resistance changes of a thin film of a doped conducting polymer, poly-o-toluidine, deposited on plastic substrates. Unlike the irreversible signals typically observed in organic films, signal reversibility in the concentration range 100–10ppm is readily achieved using a short burst of UV irradiation at room temperature in ambient air without the aid of heating or pump down cycles. Interestingly, signal response is dependent on the organic solvent used to cast the polymer film with dipolar aprotic solvents yielding films showing a strong response. There are striking differences in electrical and electronic properties including morphology of films cast from different solvents. This phenomenon is traced to polymer chain conformation in solution that is preserved in the solid state (cast film) which opens a new structural vector to tailor sensor response and selectivity. This study also expands the use of conducting polymers for the detection of vapors that were previously believed to be chemically too aggressive. [Copyright &y& Elsevier]

Abstract: The striking solvatochromic shift observed in polyaniline derivatives correlates with two solvent polarity scales, donor number (DN) and hydrogen bond acceptor scale (Taft''s β-scale). The large shift is caused by conformational changes in solution that result in dramatic differences in relative molecular weight values obtained by gel permeation chromatography (MWGPC) in different solvents. For example, for poly-o-toluidine base in the emeraldine oxidation state, a low transition energy solvent like NMP (excitonic transition, λ max 608nm) yields a very high molecular weight value (M w ∼15,000gmol−1) whereas a high transition energy solvent like CHCl3 (excitonic transition, λ max 570nm) yields an absurdly low value (M w ∼650gmol−1). An absolute molecular weight value, M w ∼4700gmol−1, was obtained for the first time using laser light scattering (MWLS) suggesting that CHCl3 promotes a highly coiled chain conformation whereas NMP promotes a more expanded, rod-like conformation. A similar trend is observed for poly-o-toluidine base in the fully oxidized pernigraniline oxidation state (Pierels transition). This suggests that even though the Pierels and excitonic transitions have different molecular origins their conformation driven solvatochromic shifts trend in a similar fashion which is different from thermochromic trends reported in previous studies. [Copyright &y& Elsevier]

The article presents the study that demonstrated that synthesis of catalyst-free synthesis of oligoanilines and polyaniline nanofibers using H2O2. The study demonstrated the synthesis of bulk quantities of polyaniline nanofibers using H2O2 oxidant without added catalyst. It also revealed the synthesis of oligoanilines of controlled molecular weight using H2O2.

Review: 49 refs. [ABSTRACT FROM AUTHOR]

CVD-grown single layer graphene undergoes rapid photochemical oxidation in the presence of ultraviolet light and oxygen. The oxidation results in a homogeneous decay of the graphitic material; no nanoscale line cracks or pits were observed with an atomic force microscope. The conductivity of the graphene film decreases with an increasing degree of oxidation. It is crucial to understand and enhance the photochemical stability of graphene for its long term use as a transparent conducting material. [ABSTRACT FROM AUTHOR]

Bulk quantities of parent polythiophene nanofibers can be synthesized rapidly and in one step by chemical oxidative polymerization of thiophene by FeCl3 using freeze-dried vanadium pentoxide nanofibers as seeds. [ABSTRACT FROM AUTHOR]