A Sensor To Help Your Smartphone Detect Toxic Gases

                Researchers have developed a cheap sensor that can be integrated to electronic circuits and can enable smartphones to detect toxic gases within seconds. Researchers said the chemical sensor’s electrical conductivity increases up to 3,000 times when it is exposed to electrophilic toxic gases. They integrated the sensor into the electronic circuit in a near-field communication (NFC) tag, which is embedded in smart cards. This technology made it possible for smartphones to detect toxic gases in five seconds at a low concentration (10 parts per million). Today people are subject to risks of being exposed to toxic gases derived from natural sources and currently available toxic gas sensors are expensive, bulky, heavy and difficult to operate.

The new device consists of a group of carbon nanotubes (CNTs) individually wrapped with supramolecular polymers – clusters of monomers held together through weak interactions – which reduces its manufacturing price. CNTs alone are highly conductive materials, but when they are wrapped with supramolecular polymers, they become poor conductors. The supramolecular polymers were designed so that weakly-bound sites in the molecules are dissociated when these sites are exposed to toxic gases. Users can determine the presence of toxic gas by holding an NFC-compatible smartphone over a sensor-embedded NFC tag while making sure that communication between the two devices is intact.