Rapid prototyping of carbon-based chemiresistive gas sensors on paper

This paper describes a rapid, solvent-free, two-step procedure for the fabrication of selective gas and vapor sensors from carbon nanotubes and graphite on the surface of paper that overcomes challenges associated with solvent-assisted chemical functionalization and integration of these materials into devices. The first step generates solid composites from carbon nanotubes (or graphite) and small molecules (chosen to interact with specific types of gases and vapors) by mechanical mixing and subsequent compression into a form similar to a conventional pencil "lead". The second step uses mechanical abrasion ("drawing") of these solid composites on the surface of paper to generate functional devices. The use of diverse composites yields sensing arrays capable of detecting and differentiating gases and vapors and part-per-million concentrations.