The present work focuses on developing and fabricating gas sensors on textile substrates to integrate active environmental monitoring in everyday fabrics: versatile production techniques such as inkjet printing have made it possible to transport a technology normally confined to traditional electronics into the world of smart fabrics and e-textiles. In order to achieve this, the research effort concentrated on producing gas-sensitive materials suitable for the formulation of specialty inks. Specifically, this thesis’ target was the synthesis of graphene and based composites (rGO@SnO2 and rGO@SnO2/Pt) as chemiresistive substances for the detection of gaseous pollutants. Liquid-Phase Exfoliation and chemical reduction were utilized as the literature suggests they are most promising for industrial scale-up. Additionally, this work emphasizes using non-complex methodologies for producing graphene-based hybrids by exploiting limited production times and facile chemical synthesis routes. This approach demonstrates the ability to easily obtain nanocomposites with tunable properties. The formulation of aqueous nano-inks led to the creation of stable dispersion suited for inkjet printing of fully functional devices. The response (ΔR/R0 vs. ppm) was evaluated using a testing vessel ad hoc designed and 3D printed. The gaseous analytes were selected to span the relative polarity scale: 2-propanol, acetone, benzene, and hexane. The printed devices’ performance showed a dependence of the resistance variation on both the number of printed layers and the polarity of the pollutant: compounds possessing a relative polarity factor over 0.35 elicited a stronger response (up to ~3% for 2500ppm) for 6 and 8 consecutive layers of printing. The results underline how the present work can represent a link between a rigorous academic approach to materials’ synthesis and a practical production route, thus opening further investigation routes focused on more seamless fabrication/integration processes.
Il presente lavoro è focalizzato sullo sviluppo e la fabbricazione di sensori pr gas su tessuti per l’integrazione del monitoraggio ambientale in stoffe comuni. Tecniche di produzione versatili come la stampa inkjet hanno reso possibile il trasporto di tecnologie normalmente confinate all’elettronica tradizionale nel mondo delle smart fabrics ed e-textiles. Al fine di raggiungere questo obiettivo, la ricerca è stata concentrata sulla produzione di materiali sensibili ai gas per la formulazione di inchiostri. Specificatamente, l’obiettivo di questa tesi è la sintesi di grafene e suoi compositi (rGO@SnO2 e rGO@SnO2/Pt) come sostanze chemiresistive per la detezione di inquinanti gassosi. L’esfoliazione in fase liquida e la riduzione chimica sono state utilizzate in quanto tecniche più promettenti per un’espansione su scala industriale. Inoltre, questa tesi si concentra sull’impiego di tecniche non complesse per la prosuzione degli ibridi a base grafene, sfruttando tempi di produzione contenuti e sintesi chimiche semplici. Questo approccio dimostra la possibilità di ottenere facilmente nanocompositi con proprietà controllabili. La formulaziuone di nano-inchiostri a base acquosa hanno permesso la creazione di dispositivi stampati funzionanti. La risposta di tali dispositivi (ΔR/R0 vs. ppm) è stata valutata utilizzando una camaera progettata ad hoc e stampata 3D. Gli analiti gassosi sono stati selezionati in modo da coprire l’intera finestra di polarità relativa: 2-propanolo, acetone, benzene ed esano. La performance dei dispositivi stampati mostra come la variazione di resistenza dipenda sia dal numero di strati stampati, sia dalla polarità dell’inquinante: composti chimici con un fattore di polarità relativa superiore a 0.35 hanno indotto una risposta superiore (fino al ~3% a 2500ppm) per 6 e 8 strati di stampa consecutivi. I risultati ottenuti sottolineano come questo lavoro possa rappresentare un punto di collegamento tra un approccio rigoroso e accademico alla sintesi dei materiali ed un metodo di produzione più pragmatico. Ciò apre la via ad una ricerca concentrata su processi di integrazione e fabbricazione futuribili.
Inkjet printing technology for functionalization and valorization of textiles
MARCHI, CLAUDIO
2021/2022
Abstract
The present work focuses on developing and fabricating gas sensors on textile substrates to integrate active environmental monitoring in everyday fabrics: versatile production techniques such as inkjet printing have made it possible to transport a technology normally confined to traditional electronics into the world of smart fabrics and e-textiles. In order to achieve this, the research effort concentrated on producing gas-sensitive materials suitable for the formulation of specialty inks. Specifically, this thesis’ target was the synthesis of graphene and based composites (rGO@SnO2 and rGO@SnO2/Pt) as chemiresistive substances for the detection of gaseous pollutants. Liquid-Phase Exfoliation and chemical reduction were utilized as the literature suggests they are most promising for industrial scale-up. Additionally, this work emphasizes using non-complex methodologies for producing graphene-based hybrids by exploiting limited production times and facile chemical synthesis routes. This approach demonstrates the ability to easily obtain nanocomposites with tunable properties. The formulation of aqueous nano-inks led to the creation of stable dispersion suited for inkjet printing of fully functional devices. The response (ΔR/R0 vs. ppm) was evaluated using a testing vessel ad hoc designed and 3D printed. The gaseous analytes were selected to span the relative polarity scale: 2-propanol, acetone, benzene, and hexane. The printed devices’ performance showed a dependence of the resistance variation on both the number of printed layers and the polarity of the pollutant: compounds possessing a relative polarity factor over 0.35 elicited a stronger response (up to ~3% for 2500ppm) for 6 and 8 consecutive layers of printing. The results underline how the present work can represent a link between a rigorous academic approach to materials’ synthesis and a practical production route, thus opening further investigation routes focused on more seamless fabrication/integration processes.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/192171