Plasma-treated polymer as humidity sensing material—a feasibility study

Plasma treatment of polymers (surface modification) has been carried out for a long time namely for adhesion improvement and biomedical applications, as it is known to improve the wettability (increase in hydrophilicity) of the polymer surface. It was noted that although extensive work in this area has been carried out, no literature is available on the possible use of plasma-treated/modified polymers for use as humidity sensors. With this in mind, work has been carried out to study the possible use of plasma surface treatment of polymers for humidity sensing. In this communication, we report to the best of our knowledge for the first time humidity sensing by argon plasma-treated polymer namely PMMA with encouraging results. The argon plasma-treated PMMA was characterized by FTIR, XPS, SEM, and contact angle measurements. A capacitive RH sensor was fabricated using the argon plasma-treated PMMA as the dielectric for relative humidity sensing. The sensors fabricated from argon plasma-treated PMMA showed improvement in their sensitivity in 0–40% RH range.