Flexible, all-organic chemiresistor for detecting chemically aggressive vapors

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Single-walled carbon nanotubes (CNTs) are promising materials for gas sensors due to their unique electrical properties.
• Developing robust and sensitive sensors for oxidizing vapors at room temperature remains a challenge.

Purpose of the Study:

• To develop and characterize chemiresistors based on single-walled carbon nanotube (CNT) films on cellulosic substrates.
• To evaluate the performance of these sensors in detecting aggressive oxidizing vapors under ambient conditions.

Main Methods:

• Fabrication of thin films of CNT bundles on paper and cloth substrates using inkjet printing.
• Testing the chemiresistors' response to nitrogen dioxide and chlorine at parts per billion (ppb) levels at room temperature.
• Assessing sensor robustness, signal recovery, baseline drift, and performance under mechanical stress (bending).

Main Results:

• Chemiresistors detected nitrogen dioxide at 250 ppb and chlorine at 500 ppb.
• Inkjet-printed CNT films on acid-free paper demonstrated superior robustness compared to dip-coated films on plastic.
• Sensors exhibited low variation, spontaneous signal recovery, negligible baseline drift, and maintained performance after creasing.

Conclusions:

• Cellulosic-based CNT chemiresistors are effective for detecting hazardous oxidizing vapors at low concentrations in ambient air.
• Inkjet printing offers a viable method for creating robust and high-performance CNT gas sensors on flexible substrates.
• These sensors present a promising platform for portable and wearable gas detection applications.