Scalable manufacturing of fibrous nanocomposites for multifunctional liquid sensing

• Published in: Nano today Vol. 40; p. 101270
• Main Authors: Goodman, Sheila M., Tortajada, Ignacio Asensi, Haslbeck, Florian, Oyulmaz, Kaan Yüksel, Rummler, André, Sánchez, Carlos Solans, País, Jose Torres, Denizli, Haluk, Haunreiter, Kurt J., Dichiara, Anthony B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2021
• Subjects: Carbon nanotubes; Cellulose nanofibrils; Leak detection; Liquid sensing; Paper-based electronics; Carbon nanotubes; Liquid sensing; Cellulose nanofibrils; Paper-based electronics; Leak detection
• ISSN: 1748-0132; 1878-044X
• DOI: 10.1016/j.nantod.2021.101270

•Continuous production of electrically conductive paper nanocomposite at pilot scale.•Superior interfacial properties demonstrated by spectroscopy and tape peeling tests.•Record sensitivity to liquid water enabled by the hierarchical swelling structure.•Development of a robust, reliable and inexpensive remote leak-monitoring device.•Model based on equivalent circuit of resistors agrees well with experimental data. [Display omitted] Cellulose-based paper electronics is an attractive technology to meet the growing demands for naturally abundant, biocompatible, biodegradable, flexible, inexpensive, lightweight and highly miniaturizable sensory materials. The price reduction of industrial carbon nanotube (CNT) grades offers opportunities to manufacture electrically conductive papers whose resistivity is responsive to environmental stimuli, such as the presence of water or organic solvents. Here, a highly sensitive paper nanocomposite is developed by integrating CNTs into a hierarchical network of pulp fibers and nanofibrillated cellulose. The aqueous-phase dynamic web forming process enables the scalable production of sensory paper nanocomposites with minimal nanoparticle loss due to the tailored interfacial bonding between CNT and cellulose components. The resulting materials are applied as multifunctional liquid sensors, such as leak detection and wave monitoring. The sensitivity to liquid water spans an outstanding four orders of magnitude even after 30 cycles and 6-month natural aging, due to the hydroexpansion of the hierarchical cellulose network, which alters the intertube distance between neighboring CNTs. The re-organization of percolated CNTs modifies the electron transport in wet areas of the sheet, which can be predicted by an equivalent circuit of resistors for the rapid detection and quantification of various liquids over large surfaces.