sciencetech-blog

comments

In what looks like an optical illusion, scientists have found a way to defy gravity by making water run uphill.

The technique works using a material that has thousands of tiny electroplated metal bristles that move in response to a magnetic field.

When the magnetic field changes, so do the bristles, forcing the liquid that sit against them into an unexpected direction.

Scroll down for video 

The scientists in Massachusetts hope the material could someday be used to create glare-resistant windows and rain-resistant clothing.

Each microhair, made of nickel, is about 70 microns high and 25 microns wide - about one-fourth the diameter of a human hair.

The researchers created an array of the microhairs onto an elastic, transparent layer of silicone.

In tests, the magnetically-activated material directed not just the flow of fluid, but also light - much like window blinds tilt to filter the sun.

The technique works using a material that has thousands of tiny electroplated metal bristles that move in response to a magnetic field. When the magnetic field changes, so does the direction of the bristles

Researchers say the work could lead to waterproofing and anti-glare products, such as 'smart windows' for buildings and cars.

'You could coat this on your car windshield to manipulate rain or sunlight,' said Yangying Zhu, a graduate student in MIT's Department of Mechanical Engineering.

'So you could filter how much solar radiation you want coming in, and also shed raindrops. This is an opportunity for the future.'

In the near term, the material could also be embedded in lab-on-a-chip devices to magnetically direct the flow of cells and other biological material through tiny channels.

The inspiration for the microhair array comes partly from nature, Ms Zhu says.

Researchers say the work could lead to waterproofing and anti-glare products, such as 'smart windows' for buildings and cars. Pictured here is water flowing up hill (right) due to the magnetic field and bristles

For example, human nasal passages are lined with cilia - small hairs that sway back and forth to remove dust and other foreign particles.

'We see these dynamic structures a lot in nature,' Ms Zhu says.

'So we thought, 'What if we could engineer microstructures, and make them dynamic?' This would expand the functionality of surfaces.'

In principle, she says, more complex magnetic fields could be designed to create intricate tilting patterns throughout an array.

Since the material is flexible, Wang says that it may even be woven into fabric to create rain-resistant clothing.

'A nice thing about this substrate is that you can attach it to something with interesting contours,' Miss Wang says.

'Or, depending on how you design the magnetic field, you could get the pillars to close in like a flower. You could do a lot of things with the same platform.'