Researchers at Stony Brook University, part of the State University of New York (SUNY) system, have patented a new method for measuring dew point and detecting icing conditions using a graphene oxide film, offering a potentially far cheaper alternative to the expensive chilled-mirror hygrometers currently used for precision humidity measurement.
Dew point - the temperature at which moisture in the air begins condensing on a surface - is considered a more reliable humidity metric than relative humidity, since it stays constant regardless of temperature changes. Chilled-mirror hygrometers, which cool a surface to find that exact condensation point, are regarded as the most accurate instruments for the job and are widely used in labs and industrial settings requiring precise, repeatable humidity control. However, these laboratory-grade instruments are notoriously expensive and can be temperamental in operation.
The Stony Brook team's approach instead relies on the adsorption behavior of graphene oxide. A thin molecular layer of water forms on the graphene oxide film's surface, and the sensor detects the first-order phase transition as that water turns to ice. Because proton conduction in graphene oxide is closely tied to both humidity levels and temperature variation, the film can be used to directly and precisely determine dew point, functioning as a low-cost hygrometer platform without the expense of conventional chilled-mirror systems.
The technology, developed by inventor Vladimir Samuilov, is being offered for licensing through the Research Foundation for SUNY, which manages technology transfer for the university system. Beyond standard dew-point hygrometers, the university points to potential uses in general moisture and humidity detection, humidity control systems, and icing-condition detection in aviation.
