Efficient selection of semiconducting SWCNTs of large diameter range (0.8-1.6 nm) on demand is demonstrated. Different diameters of SWCNT are systematically selected by tuning the alkyl side-chain lengths of the wrapping polymers of similar backbone. The exceptional quality and high concentration of the SWCNTs is validated by the outstanding optical properties and the highly performing random network ambipolar field-effect transistors.

We present a method to achieve stable dispersions of multiwalled carbon nanotubes (MWCNT) in tetrahydrofuran for several days. The physical chemistry of this method is based on the π-π stacking interactions between MWCNT and an azobenzene derivative, Disperse Orange 3 (DO3). Evidence of this interaction was obtained using UV-vis absorption spectroscopy. Our results suggest that there is a weight ratio DO3/MWCNT beyond which interactions are strong enough to achieve stable dispersions of MWCNT for at least 45 days.

A new biodegradable photoresponsive material was developed using poly(lactic acid) (PLA) as the matrix material and Disperse Orange 3 (DO3) as photoisomerizable azo-dye. It was observed that the addition of multi-walled carbon nanotubes (MWCNTs) leads to a new phenomenon consisting of an enhancement of the optical anisotropy in a wide range of temperatures. In particular, the optical anisotropy increases 100% at room temperature. Moreover, the material containing MWCNTs shows a faster optical response that is evidenced as an increase in the growth rate of optical anisotropy. Spectroscopic data is provided to study the interaction among DO3, MWCNTs and PLA. The enhancement of optical anisotropy obtained with the addition of MWCNTs was related to the glass transition temperature (T g ) of each material. Maximum optical anisotropy was obtained 15 • C below the T g for both materials. Results are interpreted in terms of the interactions among DO3, MWCNTs and PLA and the packing density of the dye into the polymer chains.

What exactly is “scientific culture”? How does it relate to science communication, non-formal education or artistic interactions with the scientific world? That was the topic of the 14th International Summer School of Mind, Brain and Education (ISMBE), held 1–4 October 2019 at the Ettore Majorana Centre for Scientific Culture in Erice (Sicily), Italy. The ISMBE has a long history of bringing together researchers from diverse fields to catalyze research relating to cognitive science and neuroscience through to education, and the directors of the School, Drs. Kurt Fischer, Antonio Battro and Sebastián Lipina considered that the boundary between these fields and scientific culture was subtle enough to demand a conference on the subject and asked us to organize such a meeting.

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Abstract. Azo-dye molecules may suffer from bleaching under certain illumination conditions. When this photoinduced process occurs, it generates an irreversible effect that is characterized by the loss of absorption of the dye molecule. Moreover, the well-known isomerization of azodye molecules does not occur anymore. In this work it is shown how the addition of a small amount of multi-walled carbon nanotubes (MWCNTs) helps to decrease the bleaching effect in a photosensitive guest-host azo-polymer film. Two different systems were fabricated using an epoxy resin as polymer matrix. An azo-dye, Disperse Orange 3, was used as photosensitive material in both systems and MWCNTs were added into one of them. The optical response of the polymeric systems was studied considering the degree of photoinduced birefringence. Photobleaching of the azo-dye was observed in all cases however, the effect is lower for the composite material containing 0.2 wt % MWCNTs. The weak interaction between MWCNTs and dye molecules is less favorable when the material is heated. The optical behavior of the heated composite material suggests that carbon nanotubes can be potentially used as azo dye dispensers. The results are interpreted in terms of the non-covalent interaction between azo-dye molecules and MWCNTs.

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Pocos estudios buscan entender la experiencia del visitante adolescente en museos y centros de ciencias en América Latina. El presente estudio es de carácter cualitativo y tiene como objetivo comprender la experiencia de adolescentes en una visita fuera del contexto escolar en el Centro Cultural de la Ciencia (C3), el museo interactivo de ciencia más reciente en Buenos Aires, Argentina. Analizamos la visita de cinco grupos, entre 15 y 18 años, de escuelas públicas. Los resultados mostraron que hubo interactividad durante la visita, un aspecto deseado en esos espacios culturales - y esto ocurrió con mucha intensidad en dos de las tres esferas según el modelo teórico adoptado: entre los visitantes y entre los visitantes y los objetos. La tercera esfera, la interacción entre visitantes y mediadores, no tuvo una fuerte presencia. Observamos también que la mayoría de las conversaciones que surgieron entre los visitantes fueron sobre el funcionamiento de la exposición y no sobre temas científicos, como se esperaba en un museo de ciencia.