Fabrication of Solid-State Gas Sensors by Drawing: An Undergraduate and High School Introduction to Functional Nanomaterials and Chemical Detection

Abstract

Carbon nanomaterials have promising utility in chemical sensing including applications in preserving occupational safety, monitoring of environmental pollution, and human health. While recent advances in device fabrication and molecular design of functional materials have enabled rapid fabrication of chemical sensors from carbon nanomaterials, limited efforts have focused on translating these discoveries into undergraduate curriculum. This paper describes a safe and engaging laboratory exercise that introduces undergraduates and younger students to modern nanoscience while illustrating fundamental principles of general chemistry that include concepts of orbital hybridization, allotropes, and intermolecular interactions. Solid-state devices are prepared on shrinkable polymer film substrates equipped with hand-drawn graphite electrodes. Chemiresistive sensing materials, carbon nanotubes (CNTs) and graphite powder, are compressed into pellets and drawn directly into this device architecture to produce functional sensors capable of detecting and differentiating gases and vapors based on differences in intermolecular interactions.