Biopolymer-based materials have been of particular interest as alternatives to synthetic polymers due to their low toxicity, biodegradability and biocompatibility. Among them, chitosan is one of the most studied ones and has recently been investigated for the application as solid state polymer electrolytes. Furthermore, it can serve as a host for luminescent species such as rare earth ions, opening up the possibility of combined electro-optical functionality, of particular interest for electroluminescent devices. In this study, we perform a fundamental, initial, investigation of chitosan based luminescent materials doped with EuIII and LiI triflate salts, from the structural, photophysical and conducting points of view. Because the host presents a broad emission band in the blue to green, while EuIII emits in the red, fine-tuning of emission colour and/or generation of white light is proven possible, by proper combination of optimized composition and excitation scheme. Europium lifetimes (5D0) are in the range 270-350 µs and quantum yields are up to 2%. Although LiI does not interfere with the luminescent properties, it grants ion-conducting properties to the material suggesting that a combination of both properties could be useful in the development of electro-luminescent devices.

NiO nanoparticles with an average size of 15 nm were prepared by a simple, reproducible and low-cost controlled method, using nickel nitrate hexahydrate (Ni(NO3)2·6H2O). These nanoparticles were added to an agar-based polymer electrolyte formula, resulting, after reflux and solution casting, in a proton conducting membrane. The highest ionic conductivity values of 5.19x10-5 S cm-1 at room temperature and 3.32x10-4 S cm-1 at 80 ºC, were obtained for the sample with 50 wt. % of acetic acid and 0.25 g of NiO. Moreover, the samples showed 75 % of transparency in the visible region, a homogeneous surface and mainly amorphous structure. All the obtained results suggest that agar-based polymer electrolyte with NiO nanoparticles are promising candidates for electrochemical devices application.

Chemistry is a experimental science and should be taught emphasizing the experimental work at laboratories. Brazilian teachers either in secondary level teaching as well at University gave minor attention in laboratory experiments as a tool to improve the quality of the teaching. Adelino Leal published a monograph in 1926 which emphasizes the experimental work in the teaching of Chemistry. The French chemist Jungfleisch had a important influence in the Adelino Leal's work and was the main reference for both his work and published books.

Foram preparadas amostras de hidroxietil celulose (HEC) enxertada com poliéteres para aplicação como eletrólitos sólidos poliméricos. Amostras comerciais de HEC foram caracterizadas por ¹H e 13C RMN, FTIR e viscosimetria, visando a determinação dos respectivos graus de substituição molar (MS), grau de substituição (DS) e grau de polimerização (DP). Amostras comerciais de diaminas de poli(óxido de etileno) (POE) e poli(óxido de propileno) (POP) foram também caracterizadas antes de serem convertidas nos correspondentes diisocianatos. As redes foram obtidas através de reações de condensação das HEC com os diisocianatos e caracterizadas por FTIR, UV-Vis, difração de raios-X e análises térmicas, a fim de definir suas Tg.

Commercial samples of hydroxyethyl cellulose (HEC) were characterized by 1H and 13C NMR, FTIR and viscosimetry, in order to obtain their average molar substitution (MS), average degree of substitution (DS) and average degree of polymerization (DP). Commercial samples of poly(ethylene oxide) diamines (POE) and poly(propylene oxide) diamines (POP) were also characterized before being converted into their corresponding diisocyanates. The networks were obtained by the condensation reaction of each HEC with the diisocyanates. The products were characterized by FTIR, UV-Vis, X-ray diffraction and also DSC to determine the glass transition temperatures.