Static from Styrofoam and wind harvested for electricity

If you've ever had a packing peanut stick to your clothes as you unbox your Amazon delivery, then you know that Styrofoam is pretty good at generating static electricity. A new invention turns that quality into a workable energy-saving solution.

Polystyrene, more commonly known in the US as Styrofoam, might be a handy material for cushioning delicate goods when they are shipped, or for keeping your takeout coffee warm, but it's a scourge in landfills where it can take up to 500 years for the material to degrade. Still, global production of the plastic-based foam sits at around 26 million tons per year, a number that is predicted to rise. It is estimated that Americans alone throw away 25 billion Styrofoam cups per year.

Seeking a way to put all that polystyrene waste to use, researchers at the Royal Melbourne Institute of Technology (RMIT), in collaboration with Riga Technical University in Latvia, have invented a thin patch made out of multiple layers of the material. Each layer is about one-tenth the thickness of a human hair and, when air is blown across it, static electricity is produced, which can then be harvested. In testing, the patches were able to produce about 230 volts, about double of what's produced by standard US outlets.

The researchers who invented the patches believes they could make use of the exhaust from air conditioning units to generate power to offset the carbon footprint of cooling systems and reduce their energy demand by about five percent. RMIT has filed a provisional patent for the patches and is seeking to develop the invention with commercial partners.

“The biggest numbers come from a compression and separation, where you've got faster speeds and bigger motion, while smaller motion generates less energy,” said lead researcher Peter Sherrell. “This means that in addition to air conditioners, integrating our patches in high traffic areas such as underground walkways could supplement local energy supply without creating additional demand on the grid.”

Really fat

When inventing the patch, the RMIT research team experimented with a range of single-use plastics to optimize energy production.

“We've studied which plastic generates more energy and how when you structure it differently – make it rough, make it smooth, make it really thin, make it really fat – how that changes all this charging phenomenon,” Sherrell said. “The culmination of all our learning has gone into developing these simple little patches that can create quite a large amount of energy."

The researchers also decoded what causes the static electricity effect at the nanoscale for what they believe is the first time, and came up with a way to harness the somewhat chaotic process to produce a reliable current.

“We’ve figured out how to make the insides of reformed polystyrene rub across each other in a controlled way, making all the charges pull in the same direction to produce electricity,” Sherrell explained. “Over the past few years, we’ve been gaining a better understanding about what is happening.

“Plastics are like millions of little strands and when you put two plastic films together these strands get knotted together. When these knots break, there's a little bit of charge on each part of that broken bond.”

Not only are the patches good at producing electricity but they should prove to be extremely durable as well.

“The great thing here is the same reason that it takes 500 years for polystyrene to break down in landfill makes these devices really stable – and able to keep making electricity for a long time,” Sherrell concluded.

The research has been published in the journal Advanced Energy and Sustainability Research.

Source: RMIT