Thermally Driven Selective Nanocomposite PS-PHB/MGC Nanofibrous Conductive Sensor for Air Pollutant Detection

The potentials to use the working temperature to tune both the sensitivity and the selectivity of a chemical sensor based on a nanostructured and nanocomposite polymer layer have been investigated and described. Thus, in a single step, a peculiar chemical layer was grown up onto IDE (Interdigitated Electrode) microtransducers by electrospinning deposition and using a single-needle strategy. The 3-component nanofibers, obtained from a mixture of polystyrene and polyhydroxibutyrate (insulating thermoplastics) and a known concentration of mesoporous graphitized carbon nanopowder, appeared highly rough on the surface and decorated with jagged islands but homogeneous in shape and diameter, with the nanofillers aggregated into clusters more or less densely packed through the fibers. The resulting sensor was conductive at room temperature and could work between 40 and 80°C without any apparent degradation. As the fibrous sensing layer was heated, the current increased and the sensitivity to some classes of VOCs such as an oxidizing gas drastically changed depending on the working temperature. More in detail, the sensor resulted highly sensitive and selective to acetic acid at 40°C but the sensitivity fell down, decreasing by 96%, when the sensor operated at 80°C. On the other hand, although an increase in temperature caused a general decrease in sensitivity to the tested VOCs (with a maximum of 14, 81, and 78% for amine, acetone and toluene, respectively) and water vapors (with a maximum of 55%), higher temperature affected only slightly the amine permeation, thus modifying the partial selectivity of the sensor to these chemicals. Conversely, when the operating temperature increased, the sensitivity to the detected gas, NO2, increased too, reporting a ~2 ppb limit of detection (LOD), thus confirming that the temperature was able to drive the selectivity of nanocomposite polymeric sensors

Mesoscale organization of titania thin films enables oxygen sensing at room temperature

The application of titania materials to gas sensing devices based on thin films are of limited utility because they only operate at a high working temperature and exhibit in general a low sensitivity. To overcome these constraints, a new type of oxygen sensor based on mesoporous titania thin films working at room temperature under UV irradiation has been developed. The increased density of charge carriers induced by the photoconductive effect, has been used to enhance the sensitivity of the thin oxide layers. Mesostructured titania films have been prepared via self-assembly and thermal processing to remove the organic template obtaining anatase nanocrystals. The mesoporous films show a striking decrease of the current in the presence of oxygen that acts as an electron scavenger. Mesoporous samples exhibit a much higher response with respect to dense titania, due to the higher surface area and the larger number of surface defects.RAS is acknowledged for funding this project through CRP 30 L.R. 7/2007 ‘‘Bando Capitale Umano ad Alta Qualificazione annualita` 2015’’. This work was partially supported by the project ‘‘Mi ADATTI E L’ABBATTI’’- INSTM-Regione Lombardia project INSTMRL6

EXPLOITATION OF OVERRUN MACROALGAE AS MODEL TO LEAD THE CIRCULAR ECONOMY TRANSITION AND THE BIOECONOMY GROWTH

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Design and Development of Nanostructured Thin Films

Due to their unique size-dependent physicochemical properties, nanostructured thin films are used in a wide range of applications from smart coating and drug delivery to electrocatalysis and highly-sensitive sensors. Depending on the targeted application and the deposition technique, these materials have been designed and developed by tuning their atomic-molecular 2D- and/or 3D-aggregation, thickness, crystallinity, and porosity, having effects on their optical, mechanical, catalytic, and conductive properties. Several open questions remain about the impact of nanomaterial production and use on environment and health. Many efforts are currently being made not only to prevent nanotechnologies and nanomaterials from contributing to environmental pollution but also to design nanomaterials to support, control, and protect the environment. This Special Issue aims to cover the recent advances in designing nanostructured films focusing on environmental issues related to their fabrication processes (e.g., low power and low cost technologies, the use of environmentally friendly solvents), their precursors (e.g., waste-recycled, bio-based, biodegradable, and natural materials), their applications (e.g., controlled release of chemicals, mimicking of natural processes, and clean energy conversion and storage), and their use in monitoring environment pollution (e.g., sensors optically- or electrically-sensitive to pollutants