Thanks to Sarah Kellett and CSIRO Science by email comes this article about the work of Australian researchers.
“Researchers at RMIT and the Australian National University (ANU) are aiming to create a device that recharges itself when you use it. To achieve it, they are finding out how piezoelectric materials convert small mechanical movements into electricity.
“Piezoelectric films work when you deform them,” says Dr Simon Ruffell from the ANU. “If you miniaturise these films to the nano-scale, can you use them to power phones and other devices?”
The nanoscale is smaller than the microscopic – about a billionth of a metre. Nano-sized piezoelectric films could hopefully create phone batteries that charge by typing on a touch screen, and new pacemakers powered by the vibrations of the body.
The researchers created nano-sized islands of piezoelectric films and attached them to a surface. When the surface is squeezed, these nano-islands create a small charge. Microchips could increase the charge until it is large enough power a battery.
By using a machine called nanoECR developed by the ANU and Hysitron in America, Simon was able to accurately measure how much energy was created by applying a certain amount of pressure to the film.
The nanoECR has a moving diamond tip which can conduct electricity. It can precisely measure charge and pressure at the same time. “We positioned the tip to push on the nanoisland and measured the amount of electricity produced,” he said.
Knowing the voltage produced by thin films helps improve piezoelectric technology, and could lead to self-charging gadgets and medical devices.”
Piezoelectric currents are perhaps best known as those small currents produced in the minute ‘bending’ of bone during weightbearing activity. This current provides stimulation for the activity of osteoblasts and osteoclasts, guiding bone growth and structure. The current is particularly important in bone healing following a fracture and it is suspected that holding a fracture too rigidly may actually delay union.