Subscribe free to our newsletters via your
. 24/7 Space News .

New material structures bend like microscopic hair
by Jennifer Chu
Boston MA (SPX) Aug 07, 2014

The new material designed by MIT researchers is a flexible polymer "skin" coated with microhairs (white lines) that tilt in response to a magnetic field. Image courtesy the researchers.

MIT engineers have fabricated a new elastic material coated with microscopic, hairlike structures that tilt in response to a magnetic field. Depending on the field's orientation, the microhairs can tilt to form a path through which fluid can flow; the material can even direct water upward, against gravity.

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 fabricated an array of the microhairs onto an elastic, transparent layer of silicone.

In experiments, the magnetically activated material directed not just the flow of fluid, but also light - much as window blinds tilt to filter the sun. Researchers say the work could lead to waterproofing and anti-glare applications, such as "smart windows" for buildings and cars.

"You could coat this on your car windshield to manipulate rain or sunlight," says 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 a diagnostic chip's microchannels.

Zhu reports the details of the material this month in the journal Advanced Materials. The paper's co-authors are Evelyn Wang, an associate professor of mechanical engineering, former graduate student Rong Xiao, and postdoc Dion Antao.

Nature's dynamics
The inspiration for the microhair array comes partly from nature, Zhu says. For example, human nasal passages are lined with cilia - small hairs that sway back and forth to remove dust and other foreign particles. Zhu sought to engineer a dynamic, responsive material that mimics the motion of cilia.

"We see these dynamic structures a lot in nature," Zhu says. "So we thought, 'What if we could engineer microstructures, and make them dynamic?' This would expand the functionality of surfaces."

Zhu chose to work with materials that move in response to a magnetic field. Others have designed such magnetically actuated materials by infusing polymers with magnetic particles.

However, Wang says it's difficult to control the distribution - and therefore the movement - of particles through a polymer. Instead, she and Zhu chose to manufacture an array of microscopic pillars that uniformly tilt in response to a magnetic field. To do so, they first created molds, which they electroplated with nickel.

They then stripped the molds away, and bonded the nickel pillars to a soft, transparent layer of silicone. The researchers exposed the material to an external magnetic field, placing it between two large magnets, and found they were able to control the angle and direction of the pillars, which tilted toward the angle of the magnetic field.

"We can apply the field in any direction, and the pillars will follow the field, in real time," Zhu says.

Tilting toward a field
In experiments, the team piped a water solution through a syringe and onto the microhair array. Under a magnetic field, the liquid only flowed in the direction in which the pillars tilted, while being highly "pinned," or fixed, in all other directions - an effect that was even seen when the researchers stood the array against a wall: Through a combination of surface tension and tilting pillars, water climbed up the array, following the direction of the pillars.

Since the material's underlying silicone layer is transparent, the group also explored the array's effect on light. Zhu shone a laser through the material while tilting the pillars at various angles, and found she could control how much light passed through, based on the angle at which the pillars bent.

In principle, she says, more complex magnetic fields could be designed to create intricate tilting patterns throughout an array. Such patterns may be useful in directing cells through a microchip's channels, or wicking moisture from a windshield. 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," 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."


Related Links
Space Technology News - Applications and Research

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

New characteristics of complex oxide surfaces revealed
Oak Ridge TN (SPX) Jul 30, 2014
A novel combination of microscopy and data processing has given researchers at the Department of Energy's Oak Ridge National Laboratory an unprecedented look at the surface of a material known for its unusual physical and electrochemical properties. The research team led by ORNL's Zheng Gai examined how oxygen affects the surface of a perovskite manganite, a complex material that exhibits ... read more

August supermoon will be brightest this year

Manned Moon Mission to Cost Russia $2.8 Bln

Tidal forces gave moon its shape

Riddle of bulging Moon solved at last

NASA Mars Curiosity Rover: Two Years and Counting on Red Planet

Robotic Rock Climbers Could Uncover Clues to Mars' Past

Russia To Construct Landing Pad For ExoMars Mission

NASA Mars Rover Curiosity Nears Mountain-Base Outcrop

NASA's Space Launch System Boosters Office Completes Critical Design Review

NASA, Navy Prepare for Orion Spacecraft to Make a Splash

Orion spacecraft recovery practiced at sea

NASA Upgrades Its 3-D Spacecraft App

China's Circumlunar Spacecraft Unmasked

China to launch HD observation satellite this year

Lunar rock collisions behind Yutu damage

China's Fast Track To Circumlunar Mission

Robonaut Upgrades, Spacewalk Preps and Cargo Ops for ISS Crew

US EVAa Delayed; Crew Preps For Russian EVA, Robonaut Upgrades

Europe's Fifth and Final Resupply Ship Launches to Station

Science and Spacesuit Work While ATV-5 Preps for Launch

US Launches Two Surveillance Satellites From Cape Canaveral

United Launch Alliance Marks 85th Successful Launch

US aerospace firm outlines New Zealand-based space program

China to launch satellite for Venezuela

Planet-like object may have spent its youth as hot as a star

Young binary star system may form planets with weird and wild orbits

Hubble Finds Three Surprisingly Dry Exoplanets

Astronomers come up dry in search for water on exoplanets

Disney develops tool to design inflatable characters and structures

NASA Experts, Russia Sign Radiation Safety Protocol Despite Sanctions

New material structures bend like microscopic hair

Military training and simulation revenues to remain steady

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.