This study shows that polymer nanogels (well-defined cross-linked nanoparticles behaving as highly hydrated unimolecular objects) are suitable capping agents for palladium nanoparticle catalyst systems. In spite of the structurally complex nature of the catalysts, it was possible to go from acrylate-based monomers to ready-to-use and recyclable catalysts in only two-steps. First, nanogels were synthesized by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) method with sequential addition of monomers. Then, in the second step, palladium acetate was reduced to obtain ready-to-use catalysts (ca. 25 nm nanogel structures containing ca. 7 nm palladium nanoparticles). The catalytic activity was confirmed in p -nitrophenol (Nip) reduction and Suzuki cross-coupling reactions. The observed rate constants (kobs) for Nip reduction were in the range of 0.8-10.0 × 10-2 s-1 depending on the polymeric capping agent structure, with the highest value being found for nanogel-based systems. These composite catalysts also mediated the cross-coupling Suzuki reaction providing the expected products in quantitative yields under relatively mild conditions after 4 h at 50 ºC. The simplicity of catalyst preparation protocol that ensures excellent activity and the low concentration of polymer applied during the synthesis are a step forward in terms of environmental and economic prospects.

In this study, we report the synthesis of submicrometer calcium carbonate particles using the simplest approach of mixing solutions of calcium chloride and ammonium carbonate inorganic precursors in the presence of crystallization modifiers. Instead of the typical crystallization of CaCO3 into large calcite crystals with rhombohedral morphology, very small uniform spherical vaterite particles were formed with the addition of small amounts of the anionic homopolymer poly(sodium 4-styrenesulfonate) (PSS). In contrast, large spheres made of a collection of calcite polycrystallite aggregates formed in the presence of poly(acrylic acid) (PAA). Crystal growth in a pre-organized environment created by the selective distribution of CaII ions in the shell of polyestyrene-b-poly(acrylic acid) (PS-b-PAA) core-shell spherical micelles revealed a rather poor control of the size and morphology. Therefore, the PSS anionic homopolymer can be applied to the synthesis of submicrometer CaCO3 particles from solutions of inorganic salts, which is a much cheaper and sustainable method than controlled CO2 gas production and diffusion.

The present study aims at analyzing the dynamics under which the solidarity economy movement can represent a driving element of local development of territories. Therefore, it is used a sample of seven Solidarity Economic Enterprises (SEE) based in the municipality of Miranda, in the State of Mato Grosso do Sul/Brazil, which fall within in the local tourism activity and, through relations of solidarity and reciprocity which are their characteristic, hypothetically promote the development of the territory in screen. Shortly, before these premises, there was an exploratory and descriptive, using the method of multicase studies, with the aim to validate or refute this alleged relationship between solidarity economy and local development. It is conclude by analyzing the results, that the SEE investigation represent important factor in the creation and distribution of income in the municipality of Miranda, and promotes the dissemination of specific socio-cultural planning processes and promoting awareness about the use of local natural resources - contributing thus to the local development on a human scale.

El presente trabajo tiene como objetivo general analizar las dinámicas bajo las cuales el movimiento de la economía solidaria puede representar un elemento propulsor para el desarrollo local de los territorios. Para esto se vale de una muestra de siete Emprendimientos Económicos Solidarios (EES) localizados en el municipio de Miranda, en Mato Grosso do Sul, Brasil; que se insertan en la actividad turística local a través de las relaciones de solidaridad y reciprocidad que los caracterizan, y que hipotéticamente promueven el desarrollo del territorio. Luego, ante estas premisas, se realizó una investigación exploratoria y descriptiva, a través del método de estudio de multicasos para validar o refutar esta supuesta relación entre la economía solidaria y el desarrollo local. Se concluye, mediante el análisis de los resultados, que los EES investigados representan un importante factor de generación y distribución de ingreso en el municipio de Miranda, promoviendo la difusión de las especificidades socioculturales del territorio y fomentando procesos de concientización respecto del uso de los recursos naturales locales; contribuyendo así al desarrollo local a escala humana.

A engenharia de superfícies para o posicionamento de biomoléculas é uma etapa fundamental para a produção de biochips. Neste estudo, descreve-se uma nova estratégia para a preparação de nanodomínios contendo grupos ácido fosfônicos, os quais se ligam a uma família de proteínas (anexinas), de forma reversível em função da presença de íons cálcio. A abordagem desenvolvida consistiu no uso de precursores de poliestireno-b-poli(metacrilato de 2-hidroxietila) (PS-b-PHEMA) sintetizados por polimerização radicalar por transferência de átomos (ATRP) para a obtenção de cilindros de PS (fPS = 0.25-0.27) dispostos em morfologia hexagonal numa matriz de PHEMA. Os grupos hidroxila pendentes do PHEMA foram, em seguida, parcialmente (20%) convertidos em grupos ácido fosfônicos por reações sequenciais de fosforilação, sililação e metanólise. Este processo produziu derivados PS-b-P(HEMA-co-PEMA) que retêm a morfologia hexagonal, embora o grau de organização estrutural seja menor em relação aos precursores.

Surface engineering for precise positioning of biomolecules is of particular interest for controlled fabrication of biochips. In this study, a novel approach for the preparation of nanodomains with phosphonic diacid groups that were previously shown to reversibly bind to a family of proteins (annexins) in a calcium-dependent manner is described. The strategy makes use of polystyrene-b-poly(2-hydroxyethyl methacrylate) (PS-b-PHEMA) precursors prepared by atom transfer radical polymerization (ATRP) to obtain hexagonally packed PS cylinders (fPS = 0.25-0.27) in a PHEMA matrix. The pendant hydroxyl groups of PHEMA are then partially (ca. 20%) converted into phosphonic diacid groups via sequential reactions involving phosphorylation, silylation and methanolysis. This process produces PS-b-P(HEMA-co-PEMA) derivatives that still retain the hexagonal morphology, but their degree of structural organization is reduced comparatively to the precursors.

Neste trabalho investigou-se a capacidade de filmes de poli(4-vinilpiridina) (P4VP) em melhorar as propriedades de corrosão do cobre em H2SO4 0,1 mol L-1. Filmes que formam o complexo macromolecular Cu(P4VP)2(SCN)2 foram obtidos por métodos eletroquímicos ou espontaneamente (por imersão) em soluções contendo 3% de ácido acético, KSCN 0,1 mol L-1 e P4VP. As características morfológicas dos filmes e o seu efeito sobre a corrosão do cobre foram analisados por técnicas de microscopia e eletroquímicas, respectivamente. Um aumento acentuado na resistência à corrosão de amostras de cobre recobertas por filmes de P4VP gerados espontaneamente foi observado em comparação às amostras não recobertas. A melhor condição para a obtenção destes filmes consiste na imersão do cobre em soluções contendo P4VP 0,1 mol L-1 durante 3 - 4 h. Empregando-se esta metodologia, registraram-se eficiências de inibição (EI) de 94 - 98%. Para filmes gerados eletroquimicamente, a EI foi de 70 - 85%.

We report here on the ability of poly(4-vinylpyridine) (P4VP) films to improve the copper corrosion properties in 0.1 mol L-1 H2SO4. Films formed by Cu(P4VP)2(SCN)2 macromecular-complex were electrochemically or spontaneously (by immersion) grown onto copper surfaces in 3% acetic acid, 0.1 mol L-1 KSCN and P4VP containing solutions. Imaging and electrochemical techniques were employed to characterize the film morphology and evaluate its effect on the copper corrosion, respectively. A substantial increase in corrosion resistance of copper samples spontaneously coated by P4VP films was found in comparison to the uncoated ones. The optimum conditions for spontaneous growth comprise a 3 - 4 h immersion period in a 0.1 mol L-1 P4VP containing solution. Inhibition efficiencies (IE) of 94 - 98% were recorded by employing this methodology. For electrochemically grown P4VP films, the IE was 70 - 85%.

A interação do polímero poli(4-vinilpiridina) (P4VP) e íons tiocianato com cobre em soluções ácidas foi estudada através de voltametria cíclica, termogravimetria, análise elementar e espectroscopia na região do infravermelho. Observou-se que os íons Cu(I) eletrogerados em ca. -0,45 V/ECS na superfície do eletrodo promovem uma reação de complexação com P4VP e SCN-, ambos presentes em solução. O complexo polimérico eletroativo resultante cresce sobre a superfície do eletrodo como um filme e o centro metálico é oxidado para Cu(II) numa etapa subseqüente em ca. -0,23 V/ECS. De acordo com os resultados termogravimétricos, o complexo obtido é menos estável do que o P4VP puro, conforme indicado pelo abaixamento da temperatura inicial de degradação de ca. 400 ºC (P4VP) para ca. 200 ºC (complexo). A análise elementar do filme revelou uma composição química de 2:1:2 para P4VP:Cu:SCN- e os espectros na região do infravermelho indicaram que tal complexo polimérico é formado por um centro metálico de cobre coordenado pelos átomos de nitrogênio dos anéis piridínicos e íons tiocianato.

The interaction of poly(4-vinylpyridine) (P4VP) and thiocyanate ions with copper in acid solutions was studied by cyclic voltammetry, thermogravimetry, elemental analysis and infrared spectroscopy. It is shown that at ca. -0.45 V/SCE the electrogenerated Cu(I) ions at the surface of a copper electrode induce a complexing reaction with P4VP and SCN- both present in solution. The resulting electroactive polymer-complex grows onto the electrode surface as a film, and the metallic center is further oxidized to Cu(II) in a subsequent step at ca. -0.23 V/SCE. According to thermogravimetric results, the polymer-complex is less thermally-stable than P4VP as evidenced by the lowering in the initial temperature of degradation from ca. 400 ºC (P4VP) to ca. 200 ºC (complex). The elemental analysis revealed a chemical composition of 2:1:2 for P4VP:Cu:SCN, and the infrared spectra indicated that the complex comprises a copper metallic center coordinated with nitrogen pyridinic rings (P4VP) and thiocyanate ions.