Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new way to make microstructured surfaces

30.07.2014

Method can produce strong, lightweight materials with specific surface properties

A team of researchers has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a variety of useful properties — including controllable mechanical stiffness and strength, or the ability to repel water in a certain direction.

"We have demonstrated that mechanical forces can be used to direct nanostructures to form complex three-dimensional microstructures, and that we can independently control … the mechanical properties of the microstructures," says A. John Hart, the Mitsui Career Development Associate Professor of Mechanical Engineering at MIT and senior author of a paper describing the new technique in the journal Nature Communications.

The technique works by inducing carbon nanotubes to bend as they grow. The mechanism is analogous to the bending of a bimetallic strip, used as the control in old thermostats, as it warms: One material expands faster than another bonded to it. But in this new process, the material bends as it is produced by a chemical reaction.

The process begins by printing two patterns onto a substrate: One is a catalyst of carbon nanotubes; the second material modifies the growth rate of the nanotubes. By offsetting the two patterns, the researchers showed that the nanotubes bend into predictable shapes as they extend.

"We can specify these simple two-dimensional instructions, and cause the nanotubes to form complex shapes in three dimensions," says Hart. Where nanotubes growing at different rates are adjacent, "they push and pull on each other," producing more complex forms, Hart explains. "It's a new principle of using mechanics to control the growth of a nanostructured material," he says.

Few high-throughput manufacturing processes can achieve such flexibility in creating three-dimensional structures, Hart says. This technique, he adds, is attractive because it can be used to create large expanses of the structures simultaneously; the shape of each structure can be specified by designing the starting pattern. Hart says the technique could also enable control of other properties, such as electrical and thermal conductivity and chemical reactivity, by attaching various coatings to the carbon nanotubes after they grow.

"If you coat the structures after the growth process, you can exquisitely modify their properties," says Hart. For example, coating the nanotubes with ceramic, using a method called atomic layer deposition, allows the mechanical properties of the structures to be controlled. "When a thick coating is deposited, we have a surface with exceptional stiffness, strength, and toughness relative to [its] density," Hart explains. "When a thin coating is deposited, the structures are very flexible and resilient."

This approach may also enable "high-fidelity replication of the intricate structures found on the skins of certain plants and animals," Hart says, and could make it possible to mass-produce surfaces with specialized characteristics, such as the water-repellent and adhesive ability of some insects. "We're interested in controlling these fundamental properties using scalable manufacturing techniques," Hart says.

Hart says the surfaces have the durability of carbon nanotubes, which could allow them to survive in harsh environments, and could be connected to electronics and function as sensors of mechanical or chemical signals.

###

Along with Hart, the research team included Michael de Volder of Cambridge University; Sei Jin Park, a visiting doctoral student from the University of Michigan; and Sameh Tawfick, a former postdoc at MIT who is now at the University of Illinois at Urbana-Champaign. The work was supported by the European Research Council, the Defense Advanced Research Projects Agency, and the Air Force Office of Scientific Research.

Related links

Faculty Highlight: A. John Hart

A new way to make sheets of graphene

Abby Abazorius | Eurek Alert!

More articles from Materials Sciences:

nachricht Scientist invents way to trigger artificial photosynthesis to clean air
26.04.2017 | University of Central Florida

nachricht Researchers invent process to make sustainable rubber, plastics
25.04.2017 | University of Delaware

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>