Design of eco-friendly and sustainable nanofibrous sensors for detecting environmental pollutants

Environmental monitoring of chemical and biological contaminants is an ever-growing need of both industrialized and underdeveloped countries, because of the strong impact of several anthropogenic activities on environmental and human health. A close relationship between climate change and pollution has also been proven that further enforces the risks associated to the presence of pollutants in terrestrial, water and atmospheric ecosystems for humans and other organisms. To achieve this aim with cost effective strategies, novel sensors for environmental monitoring have been designed and developed to obtain reliable values comparable to those provided by standard methods and technologies. Engineered and functionalized nanoibers (NFs) have been investigated and used to date as smart materials for a large number of advanced environmental applications. Electrospinning technology has also been employed to create high performance sensors to detect gases and volatile organic compounds (VOCs) in the air. Sensors based on polymeric ibers look extremely attractive for the low cost and great versatility of the raw materials that can: i) be easily tunable, according to the transducer used and the application of interest; ii) take part to the resulting sensing features (selectivity and sensitivity). Based on these features, some promising electrospun nanoibrous and environmentally friendly materials designed for the detection of atmospheric pollutants will be here described. The attention will be mostly focused on the challenging goal of obtaining opto/ conductive sensors for the monitoring of air pollutants employing suitable scaffolds of eco-friendly (PHB, PCL, etc.) and sustainable (recycled) nanomaterials. Biodegradability is a noteworthy feature to obtain sensing tools environmentally friendly and safe for health. However, sensors for gas monitoring (especially outdoor) must also be able to both persist intact for a reasonable shelf life and to preserve their sensing features over time, depending on the speciic application and the working period. There are operative conditions where biodegradable polymers cannot be reasonably used. In these cases, some recycled plastics (as PET and PS) can be used to develop more durable sensing materials suitable and selective for optically/electrically active molecules/particles, according to a sustainable approach. In this case, these plastics can contribute to save energy and other major resources (e.g. food, soil, water) in strategic sectors (i.e. smart packaging).