Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lawrence Livermore researchers develop efficient method to produce nanoporous metals

26.11.2014

Nanoporous metals — foam-like materials that have some degree of air vacuum in their structure — have a wide range of applications because of their superior qualities.

They posses a high surface area for better electron transfer, which can lead to the improved performance of an electrode in an electric double capacitor or battery. Nanoporous metals offer an increased number of available sites for the adsorption of analytes, a highly desirable feature for sensors.


Tiziana Bond, an LLNL engineer who is a member of the joint research team, helped developed a cost-effective and more efficient way to manufacture nanoporous metals over many scales, from nanoscale to macroscale, which is visible to the naked eye. Photo by Julie Russell/LLNL

Lawrence Livermore National Laboratory (LLNL) and the Swiss Federal Institute of Technology (ETH) researchers have developed a cost-effective and more efficient way to manufacture nanoporous metals over many scales, from nanoscale to macroscale, which is visible to the naked eye.

The process begins with a four-inch silicon wafer. A coating of metal is added and sputtered across the wafer. Gold, silver and aluminum were used for this research project. However, the manufacturing process is not limited to these metals.

Next, a mixture of two polymers is added to the metal substrate to create patterns, a process known as diblock copolymer lithography (BCP). The pattern is transformed in a single polymer mask with nanometer-size features. Last, a technique known as anisotropic ion beam milling (IBM) is used to etch through the mask to make an array of holes, creating the nanoporous metal.

During the fabrication process, the roughness of the metal is continuously examined to ensure that the finished product has good porosity, which is key to creating the unique properties that make nanoporous materials work. The rougher the metal is, the less evenly porous it becomes.

“During fabrication, our team achieved 92 percent pore coverage with 99 percent uniformity over a 4-in silicon wafer, which means the metal was smooth and evenly porous,” said Tiziana Bond, an LLNL engineer who is a member of the joint research team.

The team has defined a metric — based on a parametrized correlation between BCP pore coverage and metal surface roughness — by which the fabrication of nanoporous metals should be stopped when uneven porosity is the known outcome, saving processing time and costs.

“The real breakthrough is that we created a new technique to manufacture nanoporous metals that is cheap and can be done over many scales avoiding the lift-off technique to remove metals, with real-time quality control,” Bond said. “These metals open the application space to areas such as energy harvesting, sensing and electrochemical studies.”

The lift-off technique is a method of patterning target materials on the surface of a substrate by using a sacrificial material. One of the biggest problems with this technique is that the metal layer cannot be peeled off uniformly (or at all) at the nanoscale.

Advanced Materials Interfaces

The research team’s findings were reported in an article titled “Manufacturing over many scales: High fidelity macroscale coverage of nanoporous metal arrays via lift-off-free nanofrabication.” It was the cover story in a recent issue of Advanced Materials Interfaces.

Other applications of nanoporous metals include supporting the development of new metamaterials (engineered materials) for radiation-enhanced filtering and manipulation, including deep ultraviolet light. These applications are possible because nanoporous materials facilitate anomalous enhancement of transmitted (or reflected) light through the tunneling of surface plasmons, a feature widely usable by light-emitting devices, plasmonic lithography, refractive-index-based sensing and all-optical switching.

The other team members include ETH researcher Ali Ozhan Altun and professor Hyung Gyu Park. The team’s findings were reported in an article titled “Manufacturing over many scales: High fidelity macroscale coverage of nanoporous metal arrays via lift-off-free nanofrabication.”(link is external) It was the cover story in a recent issue of Advanced Materials Interfaces.

Ken Ma | EurekAlert!
Further information:
https://www.llnl.gov/news/lawrence-livermore-researchers-develop-efficient-method-produce-nanoporous-metals

More articles from Materials Sciences:

nachricht Barely scratching the surface: A new way to make robust membranes
13.12.2018 | DOE/Argonne National Laboratory

nachricht Topological material switched off and on for the first time
11.12.2018 | ARC Centre of Excellence in Future Low-Energy Electronics Technologies

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Magic number colloidal clusters

13.12.2018 | Life Sciences

UNLV study unlocks clues to how planets form

13.12.2018 | Physics and Astronomy

Live from the ocean research vessel Atlantis

13.12.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>