A research team at Qatar University (QU) has unveiled its latest progress to develop a cheap and efficient “electronic nose” for sensing toxic gases.

The researchers at QU’s multidisciplinary Center for Advanced Materials (CAM) are working with conducting polymers such as polyaniline, polypyrole and polythiophene to create sensors which could be used to sense gaseous pollutants in the atmosphere, a statement from the university said.

This could be of particular use in the petrochemical industry, where metal oxide sensors are currently used, but are expensive, and can only operate under high temperatures and require long recovery periods after each gas exposure. The polymer sensors would also be useful in the electronic engineering industry, for analysing gases.

Polymers are relatively inexpensive, can function in low temperatures and can be exposed repeatedly to gases – the researchers have been working to stabilise conducting polymers and reduce their weaknesses.

They have been blending them with some insulating polymers and improved their conductivity through doping them with different acids or some metal oxides in nano scale, it said.

Once dried, the blended solution can then be shaped into a thin, freestanding flexible film which is then tested for its suitability as a gas sensor. Each blend is then analysed for information about its chemical structure, thermal stability and electrical property, then exposed to various gases and its sensitivity to these gases under different atmospheric conditions is tested.

The polyaniline sensors performed particularly well in all the tests and the researchers blended it with insulating polymers such as polystyrene, polyvinyl alcohol or polyvinyl chloride to improve its mechanical strength, the statement said.

The latest laboratory tests exposed these sensors to carbon dioxide and ammonia gases, and they successfully detected the concentration of the gases, with even small changes in gas concentration reflected in the conductivity change of the polymer.

The next stage is to dope the sensors with nano metal oxides, it said. Other plans include developing sensors for detecting toxic gases such as hydrogen sulphide and nitrogen oxide. While current tests are carried out in lab conditions, field tests are scheduled to follow.

CAM director Dr Mariam Al-Ali Al-Ma’adeed said: “This research is at a really exciting stage. The lab tests have been successful in identifying new cheap and efficient ways of identifying toxic gases.”

“These sensors could play a significant role in petrochemical industry as well as having a number of uses in electronic engineering applications. We are looking forward to seeing how they perform in the field.”

The research team includes Dr Al-Ma’adeed; research associate and external manager Dr Noor Al-Thani; associate researcher Dr Nabil Madi and post-doctoral researcher Dr Jolly Bhadra. – TradeArabia News Service