RESUMEN
Stable ink dispersions of two-dimensional-layered-materials (2DLMs) MoS2 and graphite are successfully obtained in organic solvents exhibiting a wide range of polarities and surface energies. The role of sonication time, ink viscosity and surface tension is explored in the context of dispersion stability using these solvents, which include N-methyl-2-pyrrolidone (NMP), N,N-Dimethylacetamide (DMA), dimethylformamide (DMF), Cyclohexanone (C), as well as less-toxic and more environmentally friendly Isopropanol (IPA) and Terpineol (T). The ink viscosity is engineered through the addition of Ethyl-Cellulose (EC) which has been shown to optimize the jettability of the dispersions. In contrast to prior work, the addition of EC after sonication-instead of prior to it-is noted to be effective in generating a high-density dispersion, yielding a uniform film morphology. High-quality inks are obtained using C/T and NMP as solvents for MoS2 and graphite, respectively, as gauged through optical absorption spectroscopy. Electronic transport data on the solution-cast inks is gathered at room temperature. Arrays of 2D graphite-rod based inks are printed on rigid Si, as well as flexible and transparent polyethylene terephthalate (PET) substrates. The results clearly show the promise of ink-jet printing for casting 2DLMs into hierarchically assembled structures over a range of substrates for flexible and printed-electronics applications.
RESUMEN
The aim of this work was to study the optimal growth and high value-added production of the microalgae Coelastrum cf. pseudomicroporum Korshikov cultivated in urban wastewater. It was observed that C. cf. pseudomicroporum grew ideally in this medium, acting as an efficient nutrient starver. Additionally, the obtained biomass increased carotenoid cell content after saltwater stress. The effects of light intensity and salt stress on its growth rate were analysed. The results showed that this alga can grow very fast using wastewater as culture medium, reaching maximum growth rates of 1.61±0.05day-1, and tolerating strong irradiances. It was also found that under salt-stress this species could accumulate carotenoids (range 1.73-91.2pgcell-1). Moreover, a good harvesting efficiency (96.84%) was observed using Coelastrum exudates as bioflocculant of Scenedesmus sp., so Coelastrum exudates could act as a potential bioflocculant for other species.