Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

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

Pixel-array quantum cascade detector paves the way for portable thermal imaging devices: Research team from TU-Wien Center for Micro- and Nanostructures have developed a new 'cooler' sensing instrument thereby increasing energy-efficiency and enhancing mobility for diagnostic tes July 28th, 2016

Dirty to drinkable: Engineers develop novel hybrid nanomaterials to transform water July 28th, 2016

Thomas Swan and NGI announce unique partnership July 28th, 2016

Penn team uses nanoparticles to break up plaque and prevent cavities July 28th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Thomas Swan and NGI announce unique partnership July 28th, 2016

Penn team uses nanoparticles to break up plaque and prevent cavities July 28th, 2016

Beating the heat a challenge at the nanoscale: Rice University scientists detect thermal boundary that hinders ultracold experiments July 28th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

Nanomedicine

Pixel-array quantum cascade detector paves the way for portable thermal imaging devices: Research team from TU-Wien Center for Micro- and Nanostructures have developed a new 'cooler' sensing instrument thereby increasing energy-efficiency and enhancing mobility for diagnostic tes July 28th, 2016

Starpharma initiates new DEP™ drug delivery program with AstraZeneca July 27th, 2016

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

The NanoWizard® AFM from JPK is applied for interdisciplinary research at the University of South Australia for applications including smart wound healing and how plants can protect themselves from toxins July 26th, 2016

Discoveries

Pixel-array quantum cascade detector paves the way for portable thermal imaging devices: Research team from TU-Wien Center for Micro- and Nanostructures have developed a new 'cooler' sensing instrument thereby increasing energy-efficiency and enhancing mobility for diagnostic tes July 28th, 2016

Dirty to drinkable: Engineers develop novel hybrid nanomaterials to transform water July 28th, 2016

Penn team uses nanoparticles to break up plaque and prevent cavities July 28th, 2016

Beating the heat a challenge at the nanoscale: Rice University scientists detect thermal boundary that hinders ultracold experiments July 28th, 2016

Announcements

Pixel-array quantum cascade detector paves the way for portable thermal imaging devices: Research team from TU-Wien Center for Micro- and Nanostructures have developed a new 'cooler' sensing instrument thereby increasing energy-efficiency and enhancing mobility for diagnostic tes July 28th, 2016

Dirty to drinkable: Engineers develop novel hybrid nanomaterials to transform water July 28th, 2016

Thomas Swan and NGI announce unique partnership July 28th, 2016

Penn team uses nanoparticles to break up plaque and prevent cavities July 28th, 2016

Military

Beating the heat a challenge at the nanoscale: Rice University scientists detect thermal boundary that hinders ultracold experiments July 28th, 2016

Ultrasensitive sensor using N-doped graphene July 26th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Energy

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Designing climate-friendly concrete, from the nanoscale up: New understanding of concrete’s properties could increase lifetime of the building material, decrease emissions July 25th, 2016

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Researchers discover key mechanism for producing solar cells: Better understanding of perovskite solar cells could boost widespread use July 21st, 2016

Water

Dirty to drinkable: Engineers develop novel hybrid nanomaterials to transform water July 28th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Electricity generated with water, salt and a 3-atoms-thick membrane: EPFL researchers have developed a system that generates electricity from osmosis with unparalleled efficiency. Their work, featured in Nature, uses seawater, fresh water, and a new type of membrane just 3 atoms July 15th, 2016

Bouncing droplets remove contaminants like pogo jumpers: Researchers at Duke University and the University of British Columbia are exploring whether surfaces can shed dirt without being subjected to fragile coatings July 7th, 2016

Automotive/Transportation

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

Researchers improve catalyst efficiency for clean industries: Method reduces use of expensive platinum July 8th, 2016

Artificial synapse rivals biological ones in energy consumption June 21st, 2016

Industrial

Dirty to drinkable: Engineers develop novel hybrid nanomaterials to transform water July 28th, 2016

Scientists move 1 step closer to creating an invisibility cloak July 15th, 2016

Yale researchers’ technology turns wasted heat into power June 27th, 2016

Industrial Nanotech, Inc. Signs Agreement With and Receives First Purchase Order from Major New Customer in China June 6th, 2016

Construction

Designing climate-friendly concrete, from the nanoscale up: New understanding of concrete’s properties could increase lifetime of the building material, decrease emissions July 25th, 2016

Sensing trouble: A new way to detect hidden damage in bridges, roads: University of Delaware engineers devise new method for monitoring structural health July 8th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Nanotechnology is changing everything from medicine to self-healing buildings: Nanotechnology is so small it's measured in billionths of metres, and it is revolutionising every aspect of our lives April 2nd, 2016

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







Car Brands
Buy website traffic