An electronic nose on flexible substrates integrated into a smart textile

Abstract

Fabrication costs of gas sensors are decreasing due to the use of low cost flexible polymer substrates and solution based fabrication processes. This development creates new application possibilities for gas sensors and allows the installation into objects of our daily life, such as textiles. Challenges with the integration of electronic components on flexible substrates arise mainly due to strain introduced by bending the substrate. This plays an important role especially during weaving as strong mechanical forces bend flexible electronic devices to radii below 1 mm. To demonstrate that it is feasible to integrate low cost gas sensors into a textile while preserving the functionality, we developed an electronic nose system for textile integration. The electronic nose consists of four carbon black/polymer gas sensors fabricated on a flexible polymer substrate. After fabrication the substrate was cut into yarn like strips and integrated into a textile to create a smart textile with gas sensing functionalities. We used this smart textile to detect different solvent vapors and classified them accordingly. It was possible to detect single solvents such as acetone until a minimal concentration of 50 ppm. The influence of bending on sensors was studied, signal changes introduced by bending could be separated from changes due to solvent exposure. Bending of single strips to a radius below 1 mm did not alter the sensor functionality. The presented work shows the feasibility of the process in combination with textile integration.