Microhairs for Controlling Light and Water
It may not be easy to recognize always, but hair has many uses in Nature when it can be controlled. One example is small hairs called cilia in our nasal passages that remove particles as they sway. Researchers at MIT have recently replicated this behavior with a microhair array that could see some interesting and important applications in the future.
The material is made of a transparent sheet of silicone with very small nickel pillars on it. Being nickel, these pillars respond to magnetic fields by aligning with them. Similar work has been done before using polymers with magnetic particles, but using just nickel gets around issues with distribution. By controlling the tilt of the pillars, the researchers found they were able to influence the flow of fluids on them. This effect was strong enough that the researchers succeeded in getting water to go against gravity, when the material was against a wall. The researchers also discovered that the microhairs affected the light passing through the material, akin to how blinds deflect light coming through a window.
With the ability to control fluids and light levels, the researchers see this material having potential use with smart windows and car windshields. It may also find applications with labs-on-a-chip, as a means to control the flow of fluids in realtime.