Hybrid films composed of reduced graphene oxide (RG-O) and Cu nanowires (NWs) were prepared. Compared to Cu NW films, the RG-O/Cu NW hybrid films have improved electrical conductivity, oxidation resistance, substrate adhesion, and stability in harsh environments. The RG-O/Cu NW films were used as transparent electrodes in Prussian blue (PB)-based electrochromic devices where they performed significantly better than pure Cu NW films.

In this work, we report for the first time, the synthesis of several carbon nanotube (CNT)/polyaniline (PANI) nanocomposites obtained through interfacial polymerization, in which the resulting material is obtained directly as a transparent and freestanding film at the water−toluene interface. The films are obtained spontaneously with high stability and can be easily transferred with high optical quality to any kind of substrate or directly to a desirable device. Samples containing several CNT/PANI ratios have been prepared. The characterization of the resulting materials was carried out by FT-IR, UV−vis-NIR, and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, scanning and transmission electron microscopy, and conductivity measurements. The results indicate that the polymerization of aniline starts at the carbon nanotube walls, resulting in polymer-coated CNTs. A π−π interaction between the CNTs and the PANI is proposed. The formation of the self-standing films is discussed in terms of the stabilization of the water−toluene interface.

The synthesis and characterization of thin fi lms of polyaniline/carbon nanotubes nanocomposites is reported, as well as their utilization as transparent electrodes in ITO-free organic photovoltaic devices. These fi lms are generated by interfacial synthesis, which provides them with the unique ability to be deposited onto any substrate as transparent fi lms, thus enabling the production of fl exible solar cells using substrates like PET. Very high carbon nanotube loadings can be achieved using these fi lms without signifi cantly affecting their transparency ( ≈ 80-90% transmittance at 550 nm). Sheet resistances as low as 300 Ω / ᮀ are obtained using secondary polyaniline doping in the presence of carbon nanotubes. These fi lms present excellent mechanical stability, exhibiting no lack in performance after 100 bend cycles. Flexible and completely ITO-free organic photovoltaic devices are built using these fi lms as transparent electrodes, and high effi ciencies (up to 2.27%) are achieved.

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The utilization of iron‐based species (mainly metallic iron, hematite and magnetite) encapsulated into multi‐walled carbon nanotubes (CNTs) as reactants in an electrochemical synthesis is reported for the first time in this work. Prussian blue (PB) is electrosynthesized in a heterogeneous reaction between ferricyanide ions in aqueous solution and the iron‐species encapsulated into CNTs, resulting in novel CNT/PB paste electrodes. This innovative preparation route produces an intimate contact between the PB and the CNTs, which improves the stability and redox properties of PB. The PB formation and the chemical interaction between the PB and the CNTs are confirmed by Raman spectroscopy. The electrode is employed as a hydrogen peroxide amperometric sensor, resulting in a very low limit of detection (1.94 × 10−8 mol L−1) and very high sensitivity (15.3 A cm−2 M−1).

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This communication reports a simple, one-pot procedure for the synthesis and processing of transparent and conductive thin films of graphene/polyaniline nanocomposites based on an interfacial polymerization. Thin films presenting transmittance of 89% and sheet resistance of 60.6 Ω sq(-1) are spontaneously obtained and can be easily transferred to suitable substrates.

Recebido em 16/7/13; aceito em 1/10/13; publicado na web em 24/10/13 CARBON NANOSTRUCTURES (NANOTUBES AND GRAPHENE): QUO VADIS? We describe general considerations about the present and the future standing of carbon nanostructures, mainly carbon nanotubes and graphene. Basic concepts and definitions, select structure/property relationships, and potential applications are reviewed. The analysis of the global market for these nanostructures, the commercial products available currently, the role of the chemistry, the main challenges remaining and a brief view of the field in Brazil are also presented and discussed.Keywords: carbon nanotubes; graphene; nanoscience and nanotechnology. INTRODUÇÃOA última década do século XX foi marcada pela consolidação e crescimento vertiginoso de uma nova área do conhecimento, que trouxe no seu bojo a promessa de uma verdadeira revolução científica e tecnológica, derrubando antigos paradigmas, abrindo novos horizontes e rompendo fronteiras estabelecidas entre disciplinas: a nanociência e nanotecnologia (N&N). De maneira bastante simplificada, o princípio básico que suporta a N&N se baseia no fato de que propriedades da matéria dependem não só da sua composição e estrutura, como também de seu tamanho e formato. Abaixo de um determinado tamanho crítico, sempre na ordem de alguns nanômetros (daí o termo nanociência e nanotecnologia -a ciência e tecnologia da matéria em escala nanométrica), as propriedades de um determinado material se tornam diferenciadas daquelas observadas para o mesmo material em escala macroscópica. Desta forma, novos materiais, com propriedades diferenciadas, passaram a ser preparados somente pelo controle de tamanho e forma de materiais já conhecidos, ampliando significativamente o leque de oportunidades. 1 A N&N se caracteriza por uma alta multi-e interdisciplinaridade, na qual diferentes especialidades naturalmente passaram a sinergicamente compartilhar suas expertises: químicos, físicos, engenheiros, biólogos, matemáticos, médicos, ambientalistas, advogados, dentre outros, possibilitaram a compreensão de fenômenos e a geração de produtos com aplicações em potencial em todos os ramos da atividade humana: energia, agricultura, meio ambiente, bens de consumo, saúde e medicina, manufatura, construção civil, transporte, eletrônica, tecnologia da informação, cosméticos, têxteis, entretenimento, comunicação, lazer, etc.Dentre todos os novos(?) materiais oriundos da N&N, talvez os mais sintomáticos são os conhecidos genericamente como nanomateriais de carbono, dos quais os nanotubos de carbono (NTC), e mais recentemente o grafeno, são os mais representativos. Não deixa de ser fascinante a constatação de que o elemento químico símbolo da vida e massivamente associado à ciência química seja o único constituinte de alguns dos materiais mais intrigantes conhecidos. A riqueza e diversidade do elemento carbono, tão familiar aos químicos orgânicos, se manifesta também na química de materiais e na N&N.A Figura 1 apresenta algumas estruturas alótropas do carbono atualmente conh...