Direct Ink Writing of Graphene-Based Solutions for Gas Sensing

Abstract

In the energy industry, there is a great need for novel low-cost gas-sensing solutions. This is particularly true for shale gas operations where there is a need to monitor both performance and compliance with environmental regulations. Specifically, there is a need to monitor the integrity of well casings as oil and gas producers try to understand and mitigate environmental issues, as well as avoid unfair claims against the industry. To address this need, we report studies on the additive fabrication and characterization of a graphene-based gas sensor through multilayer direct ink writing of graphene-based inks. An evaporation-assisted solvent exchange method allows tunability of graphene concentration while the addition of ethyl cellulose (EC) allows tuning of rheological properties in printable ink formulations. Robotically controlled direct ink writing enables the deposition of films with arbitrary size and shape. Printed films incorporated into sensor packages exhibit voltage dependent sensitivity to chemical effects of CH4 and H2 in an Ar environment. Surface analysis of the printed sensors suggests disordered layering and orientation of the graphene flakes because of distributed nondecomposed residues of EC from film processing. Capitalizing on the EC residues to form 3D scaffolding enables the spatial arrangement of graphene flakes. The disordered arrangement of flakes resulting from their interaction with the EC residue scaffolding contributes to increased surface area availability for gas sensing.

Graphene-Oxide-Based Fluoro- and Chromo-Genic Materials and Their Applications

“…In order to prepare an ink with a suitable viscosity, adding polymeric binders is usually necessary. For example, Loh et al [ 99 ] changed the viscosity of ink by adding ethyl cellulose, thereby successfully preparing a graphene-based ink that can be used for direct ink writing. Compared with paste inks, the viscosity of liquid inks is naturally far lower and inkjet printing, gravure printing, and flexographic printing usually need liquid inks.…”

Engineering the surface morphology of inkjet printed Ag by controlling solvent evaporation during plasma conversion of AgNO3 inks

“…7,8 To broaden the range of detectable chemical or biochemical analytes, efforts have been aimed at functionalizing the electrodes with oxides, 9 carbon materials, 10 polymers, 11 and biomolecules, 12 as well as expanding the number of printable metals, including platinum (Pt), 13 palladium (Pd), 14 and bismuth (Bi). 15 The fabrication and functionalization of the electrodes can be performed by various additive manufacturing (AM) techniques that enable rapid prototyping and sustainable manufacturing such as direct-ink-writing (DIW), 16 inkjet printing (IJP), 17 screen printing, 18 and aerosol jet printing (AJP). 19 Among these techniques, IJP is a mature non-contact printing method that has been widely used in large-scale manufacturing.…”

Screen-Printing of Functionalized MWCNT-PEDOT:PSS Based Solutions on Bendable Substrate for Ammonia Gas Sensing

“…It has many advantages such as lightweight and easy preparation compared with the conventional vacuum deposition and photolithographic patterning methods. For the gas sensor applications, the printed techniques (direct-writing, inkjet-printing, screen-printing, 3D printing) provide a range of time-saving mechanisms and the full potential of sensing signals for application in the scope of gas sensors [ 1 , 2 , 3 , 4 ]. Toxic gases are major problems in human health and the environment.…”