Groups of researchers in Japan and the U.S. have jointly developed a material — a coated carbon nanotube — that could realize a low-cost, easy-to-carry toxic gas sensor that works with smartphones.

1. Japan-U.S. research team develops toxic gas sensor that can connect to
smartphones | ISweek - Industry sourcing
Groups of researchers in Japan and the U.S. have jointly developed a material — a
coated carbon nanotube — that could realize a low-cost, easy-to-carry toxic gas sensor
that works with smartphones.
The researchers at the National Institute for Material Science (NIMS) in Ibaraki
Prefecture and the Massachusetts Institute of Technology announced Thursday that the
material is a carbon nanotube coated with insulating polymer.
Carbon nanotube is normally highly conductive, but the insulating polymer serves to
significantly lower the tube’s conductivity.
But the coated polymer breaks apart when it is exposed to toxic gases, in which case the
conductivity of the tube drastically increases.
NIMS says it can make a sensor by loading this material in a chip that can exchange data
wirelessly with smartphones in close proximity just like the Suica cards used for shopping
or paying for train rides.
When toxic gas is present in the atmosphere, the material in the sensor becomes
conductive, so if people hold their smartphones over the sensor, the handsets will react.
Shinsuke Ishihara, a senior researcher at NIMS, said the Japanese team explained that
the toxic gas detectors currently used are heavy and expensive.
But with 1 gram of the new polymer, it is possible to make 4 million sensors, he said.
The researchers hope to put the material to practical use before 2020, and hope to install
the sensors at public facilities and subway station to prepare for possible terrorist attacks
such as one perpetrated by the Aum Shinrikyo religious cult in the Tokyo subway system
in 1995 using sarin nerve gas.
The researchers are thinking of establishing advanced systems, such as one that can
automatically send signals to smartphones whenever toxic gases are detected, Ishihara
said.
The sensors can be also attached directly to smartphones, Ishihara added. If there is a
smartphone app that can automatically check sensors once every few seconds, it can be
used to monitor toxic gases in real time.
MIT researchers in the meantime are hoping to use the sensors to design lightweight
radio-frequency identification badges that could be worn by soldiers on the battlefield,
according to the MIT website.

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