New metamaterial offers reprogrammable properties

January 20, 2021

Over the past 20 years, scientists have been developing metamaterials, or materials that don't occur naturally and whose mechanical properties result from their designed structure rather than their chemical composition. They allow researchers to create materials with specific properties and shapes. Metamaterials are still not widely used in everyday objects, but that could soon change. Tian Chen, a post-doc at two EPFL labs - the Flexible Structures Laboratory, headed by Pedro Reis, and the Geometric Computing Laboratory, headed by Mark Pauly - has taken metamaterials one step further, developing one whose mechanical properties can be reprogrammed after the material has been made. His research appears in Nature.

A single material with several mechanical functions

"I wondered if there was a way to change the internal geometry of a material's structure after it's been created," says Chen. "The idea was to develop a single material that can display a range of physical properties, like stiffness and strength, so that materials don't have to be replaced each time. For example, when you twist your ankle, you initially have to wear a stiff splint to hold the ankle in place. Then as it heals, you can switch to a more flexible one. Today you have to replace the entire splint, but the hope is that one day, a single material can serve both functions."

Silicon and magnetic powder

Chen's metamaterial is made of silicon and magnetic powder and has a complicated structure that allows mechanical properties to vary. Each cell within the structure behaves like an electrical switch. "You can activate and deactivate individual cells by applying a magnetic field. That modifies the internal state of the metamaterial, and consequently its mechanical properties," says Chen. He explains that his programmable material is analogous to computer devices like hard drives. These devices contain bits of data that can be written to and read from in real time. The cells in his programmable metamaterial, called m-bits, work like the bits in a hard drive - they can be switched on, making the material stiffer, or off, making it more flexible. And researchers can program various combinations of on and off to give the material exactly the mechanical properties they need at any given time.

To develop his material, Chen drew on methods from both computer science and mechanical engineering. "That's what makes his project so special," says Pauly. Chen also spent a considerable amount of time testing his material in each of its different states. He found that it could indeed be programmed to achieve various degrees of stiffness, deformation and strength.

Many research horizons

Programmable metamaterials are akin to machines, such as robots, that employ complicated, energy-intensive electronic mechanisms. With his research, Chen aims to find the right balance between static materials and machines. Reis sees a lot of potential for further research using Chen's technology. "We could design a method for creating 3D structures, since what we've done so far is only in 2D," Reis says. "Or we could shrink the scale to make even smaller metamaterials." Chen's discovery marks a fundamental step forward, as it is the first time scientists have developed a truly reprogrammable mechanical metamaterial. It opens up many exciting avenues for research and cutting-edge industrial applications.
-end-


Ecole Polytechnique Fédérale de Lausanne

Related Magnetic Field Articles from Brightsurf:

Investigating optical activity under an external magnetic field
A new study published in EPJ B by Chengping Yin, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China, aims to derive an analytical model of optical activity in black phosphorous under an external magnetic field.

Magnetic field and hydrogels could be used to grow new cartilage
Instead of using synthetic materials, Penn Medicine study shows magnets could be used to arrange cells to grow new tissues

Magnetic field with the edge!
This study overturns a dominant six-decade old notion that the giant magnetic field in a high intensity laser produced plasma evolves from the nanometre scale.

Global magnetic field of the solar corona measured for the first time
An international team led by Professor Tian Hui from Peking University has recently measured the global magnetic field of the solar corona for the first time.

Magnetic field of a spiral galaxy
A new image from the VLA dramatically reveals the extended magnetic field of a spiral galaxy seen edge-on from Earth.

How does Earth sustain its magnetic field?
Life as we know it could not exist without Earth's magnetic field and its ability to deflect dangerous ionizing particles.

Scholes finds novel magnetic field effect in diamagnetic molecules
The Princeton University Department of Chemistry publishes research this week proving that an applied magnetic field will interact with the electronic structure of weakly magnetic, or diamagnetic, molecules to induce a magnetic-field effect that, to their knowledge, has never before been documented.

Origins of Earth's magnetic field remain a mystery
The existence of a magnetic field beyond 3.5 billion years ago is still up for debate.

New research provides evidence of strong early magnetic field around Earth
New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed.

Massive photons in an artificial magnetic field
An international research collaboration from Poland, the UK and Russia has created a two-dimensional system -- a thin optical cavity filled with liquid crystal -- in which they trapped photons.

Read More: Magnetic Field News and Magnetic Field Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.