Electronics - Sensors

Aerogel for Combined Temperature and Pressure Sensing

The Internet of Things provides information collected by many devices used in everyday life. However, complex sensors are needed to feed a broad range of parameters to this network. To reduce this complexity, functional materials that are able to react to multiple stimuli must be developed.

In their full paper in Advanced Functional Materials, Xavier Crispin and co-workers from Linköping University, Sweden, report a thermoelectric polymer aerogel for pressure–temperature sensing applications. The device enables a cross-talk-free, independent assessment of pressure and temperature.

A so-called PNG aerogel is prepared by crosslinking PEDOT:PSS as a temperature-sensing component with glycidoxypropyl trimethyl siloxane (GOPS) and nanofibrillated cellulose (NFC). Current/voltage curves of a sensor constructed from this aerogel offer both readouts: pressure at fixed temperature by changing slopes and temperature at fixed pressure by y-axis intercept. However, slopes are different under the same pressure at different temperatures, indicating an insufficient decoupling of both signals.

Dimethyl sulfoxide (DMSO) vapor treatment of the aerogel decreases the aerogel’s resistance with DMSO exposure time. The Seebeck coefficient, which determines the temperature sensitivity of the aerogel, remains unaffected by DMSO treatment. Prolonged DMSO vapor exposure increases pressure sensitivity by three orders of magnitude while removing the temperature dependence of the resistance.

Although the signal of the untreated aerogel exhibits a temperature-dependent slope, this dependence disappears after 10 minutes of DSMO treatment, demonstrating a fully decoupled signal.

To learn more about this single-material, multi-parameter-sensing aerogel, please visit the Advanced Functional Materials homepage.

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