What environmental factors can be monitored using TENG-based sensors?

TENG-based sensors can monitor various environmental factors, including temperature, humidity, pressure, air flow, and the presence of specific gases or pollutants. Temperature sensors can be constructed by using materials whose triboelectric properties change with temperature, allowing the TENG output to be correlated to temperature variations. Humidity sensors can detect changes in the moisture content of the air by utilizing materials that swell or change their dielectric properties in response to humidity levels. Pressure sensors can measure pressure variations by using a TENG structure that is mechanically deformed by the applied pressure. Air flow sensors can detect the velocity of air by measuring the force exerted by the air on a TENG-based cantilever beam or flag. Gas sensors can detect the presence of specific gases or pollutants by using chemically sensitive materials that change their triboelectric properties upon exposure to the target analyte. For example, a TENG-based humidity sensor could use a hydroscopic polymer that swells with increased humidity, changing the contact force and thus the output of the TENG. A TENG-based air flow sensor could be placed near an HVAC vent to monitor air flow efficiency.