Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Rare earth oxides make water-repellent surfaces that last: Ceramic forms of hydrophobic materials could be far more durable than existing coatings or surface treatments

MIT postdoc Gisele Azimi, left, displays three of the 13 different ceramic disks made from oxides of the rare earth elements, with associate professor Kripa Varanasi. Behind them is the furnace used to convert the powdered oxides into solid ceramic form.
Photo: David Castro-Olmedo/MIT
MIT postdoc Gisele Azimi, left, displays three of the 13 different ceramic disks made from oxides of the rare earth elements, with associate professor Kripa Varanasi. Behind them is the furnace used to convert the powdered oxides into solid ceramic form.

Photo: David Castro-Olmedo/MIT

Abstract:
Water-shedding surfaces that are robust in harsh environments could have broad applications in many industries including energy, water, transportation, construction and medicine. For example, condensation of water is a crucial part of many industrial processes, and condensers are found in most electric power plants and in desalination plants.

Rare earth oxides make water-repellent surfaces that last: Ceramic forms of hydrophobic materials could be far more durable than existing coatings or surface treatments

Cambridge, MA | Posted on January 23rd, 2013

Hydrophobic materials — ones that prevent water from spreading over a surface, instead causing it to form droplets that easily fall away — can greatly enhance the efficiency of this process. But these materials have one major problem: Most employ thin polymer coatings that degrade when heated, and can easily be destroyed by wear.

MIT researchers have now come up with a new class of hydrophobic ceramics that can overcome these problems. These ceramic materials are highly hydrophobic, but are also durable in the face of extreme temperatures and rough treatment.

The work, by mechanical engineering postdoc Gisele Azimi and Associate Professor Kripa Varanasi, along with two graduate students and another postdoc, is described this week in the journal Nature Materials. Durability has always been a challenge for hydrophobic materials, Varanasi says — a challenge he says his team has now solved.

Ceramics are highly resistant to extreme temperatures, but they tend to be hydrophilic (water-attracting) rather than hydrophobic. The MIT team decided to try making ceramics out of a series of elements whose unique electronic structure might render the materials hydrophobic: the so-called rare earth metals, which are also known as the lanthanide series on the periodic table.

Since all of the rare earth metals have similar physico-chemical properties, the team expected that their oxides would behave uniformly in their interactions with water. "We thought they should all have similar properties for wetting, so we said, ‘Let's do a systematic study of the whole series,'" says Varanasi, who is the Doherty Associate Professor of Ocean Utilization.

To test this hypothesis, they used powder oxides of 13 of the 14 members of that series (excluding one rare earth metal that is radioactive) and made pellets by compacting and heating them to nearly their melting point in order to fuse them into solid, ceramic form — a process called sintering.

Sure enough, when tested, all 13 of the rare earth oxide ceramics did display strong hydrophobic properties, as predicted. "We showed, for the first time, that there are ceramics that are intrinsically hydrophobic," Varanasi says.

These rare earth oxides "are exotic materials, and interestingly their wetting properties have not been studied," he says, adding that many of the properties of the entire series are not systematically documented in the scientific literature. "This paper also gives a whole host of the properties of rare-earth oxides."

This includes, Azimi says, their morphology, surface chemistry, crystallographic structure, grain structure, sintering temperature and density — yielding "a catalog of information" about how to process and use these materials. The MIT researchers also showed that the materials have greater hardness than many others currently used in rough industrial settings.

Despite their name, rare earth metals are not particularly rare. "Some of them are as abundant as nickel or copper," Azimi says — both of which are widely used industrially.

But separating rare earth metals from the minerals in which they are found can be costly and can leave toxic residues, so their production has been limited. China is currently the world's major supplier of these elements, which have many high-tech applications.

The ceramic forms of rare earth oxides could be used either as coatings on various substrates, or in bulk form. Because their hydrophobicity is an intrinsic chemical property, Azimi says, "even if they are damaged, they can sustain their hydrophobic properties."

To prove the point, the team exposed some of these ceramics to a steam environment, similar to what they would face in a power-plant condenser. Typical polymer-based hydrophobic coatings quickly degrade when exposed to steam, but the ceramics kept their hydrophobicity intact, Varanasi says. The materials sustained their hydrophobicity even after exposure to abrasion, as well as temperatures of 1,000 degrees Celsius, Azimi says

By coating nanotextured surfaces with these ceramics at MIT's Microsystems Technology Laboratories, the team also demonstrated extreme water repellency where droplets bounced off the surface. "These materials therefore provide a pathway to make durable superhydrophobic surfaces as well, and these coatings can be fabricated using existing processes. This makes it amenable to retrofit existing facilities, Azimi says. Such extreme non-wetting properties coupled with durability could find applications in steam turbines and aircraft engines, for example.

Most prior research on hydrophobic materials and coatings has focused on surface textures and structure rather than on their intrinsic chemical properties, Varanasi says. "No one has really addressed the key challenge of robust hydrophobic materials," he says. "We expect these hydrophobic ceramics to have far-reaching technological impact."

Steve Granick, a professor of materials science and engineering and professor of chemistry at the University of Illinois at Urbana-Champaign, who was not connected with this research, says, "This discovery of intrinsic hydrophobicity is exciting and fresh. It's a terrific example of payoff from thinking outside the box."

The research, which included MIT postdoc Rajeev Dhiman and graduate students Hyuk-Min Kwon and Adam Paxson, was supported by the National Science Foundation, the Dupont-MIT Alliance, the MIT Energy Initiative and the Defense Advanced Research Projects Agency.

David L. Chandler, MIT News Office

####

For more information, please click here

Contacts:

Phone: 617-253-2700
Fax: 617-258-8762

Copyright © Massachusetts Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Govt.-Legislation/Regulation/Funding/Policy

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Novel stapled peptide nanoparticle combination prevents RSV infection, study finds April 17th, 2014

INSCX™ exchange to present Exchange trade reporting mechanism for engineered nanomaterials (NMs) to UK regulation agencies, insurers and upstream/downstream users April 17th, 2014

Nanomedicine

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

High-temperature plasmonics eyed for solar, computer innovation April 17th, 2014

Discoveries

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Announcements

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Military

'Exotic' material is like a switch when super thin April 18th, 2014

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Scalable CVD process for making 2-D molybdenum diselenide: Rice, NTU scientists unveil CVD production for coveted 2-D semiconductor April 8th, 2014

Energy

High-temperature plasmonics eyed for solar, computer innovation April 17th, 2014

Scientists Capture Ultrafast Snapshots of Light-Driven Superconductivity: X-rays reveal how rapidly vanishing 'charge stripes' may be behind laser-induced high-temperature superconductivity April 16th, 2014

Engineers develop new materials for hydrogen storage April 15th, 2014

A molecular approach to solar power: Switchable material could harness the power of the sun — even when it’s not shining April 15th, 2014

Water

Thinnest feasible membrane produced April 17th, 2014

Trees go high-tech: process turns cellulose into energy storage devices April 7th, 2014

Dais Analytic Wins SBIR Grant: Dais Analytic Receives US Army Small Business Innovation Research Grant to Further Its Demonstrated Successes in Cleaning Most Forms of Wastewater March 28th, 2014

University of Waterloo Engineering to Showcase Student Design March 14th, 2014

Automotive/Transportation

Relieving electric vehicle range anxiety with improved batteries: Lithium-sulfur batteries last longer with nanomaterial-packed cathode April 16th, 2014

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

Nanotech Business Review 2013-2014 April 9th, 2014

Heat-conducting polymer cools hot electronic devices at 200 degrees C March 31st, 2014

Industrial

Shiny quantum dots brighten future of solar cells: Photovoltaic solar-panel windows could be next for your house April 14th, 2014

Industrial Nanotech, Inc. Lands First Major Order from Pemex, Mexico’s State-Owned Oil and Gas Company April 14th, 2014

Industrial Nanotech, Inc. Announces Certification for Use in Middle East for Buildings: Nansulate(R) Energy Saving Coatings to be used by Major Middle East Energy Company April 1st, 2014

Harper Government Announces Support for U of S Nanoscience Research: Uses for New Nanostructured Coatings Range from Biomedical to Oil Sand Sectors March 29th, 2014

Construction

Scientists Produce Self-Cleaning Coatings on Glass Substrate March 17th, 2014

Iran Applying Nanotechnology in Growing Number of Industries March 10th, 2014

Colored diamonds are a superconductor’s best friend March 6th, 2014

Iranian, Spanish Scientists Investigate Thermal Stability of Nanostructured Bainitic Steel February 26th, 2014

NanoNews-Digest
The latest news from around the world, FREE







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE