Liquid graphene sensor might save li'l lives
Scientists at the University of Sussex have created a sensor that could someday keep babies from dying of sudden infant death syndrome (SIDS). It takes the form of a flexible rubber tube filled with a solution of water, oil and particles of everyone's favorite wonder material, graphene.
Made up of a one-atom-thick sheet of linked carbon atoms, graphene is highly electrically conductive. This means that the solution also conducts electricity, although its conductivity changes when the tube is stretched by even a tiny amount. That change can be detected, indicating that movement (such as the rising and falling of a breathing person's chest) is occurring.
"What we've done is similar to how you might make a salad dressing; by shaking together water and oil, you make tiny droplets of one liquid floating in the other because the two don't mix," explains lead researcher Dr. Matthew Large. "Normally, the droplets would all collect together and the liquids separate over time … We've resolved this by putting graphene in. The graphene, which is an atom thick, sits at the surface of the droplets and stops them from coalescing."
"When the graphene particles are assembled around the liquid droplets, electrons can hop from one particle to the next; this is why the whole liquid is conductive," he continues. "When we stretch our sensors we squeeze and deform the droplets; this moves the graphene particles further apart and makes it much harder for the electrons to hop across the system."
If such sensors were attached to sleeping babies in the form a fitness tracker-like band – or integrated into their clothing – they could monitor the infants' heartbeat and respiration, causing an alarm to sound if either stopped. The technology could also be used to monitor adults with conditions such as sleep apnea, or it could even find its way into sportwear for athletes who want to keep track of their heart or respiration rates.
The sensitivity of the system is said to be much higher than that of many other motion-detection technologies, plus the sensors should reportedly be easy and inexpensive to manufacture. The university has partnered with the company Advanced Materials Development to commercialize the technology.
A paper on the research was recently published in the journal Nanoscale.
Source: University of Sussex