Snap to attention: Polymers that react and move to light

November 08, 2013

PITTSBURGH--Microvehicles and other devices that can change shape or move with no power source other than a beam of light may be possible through research led by the University of Pittsburgh. The researchers are investigating polymers that "snap" when triggered by light, thereby converting light energy into mechanical work and potentially eliminating the need for traditional machine components such as switches and power sources.

"I like to compare this action to that of a Venus flytrap," says M. Ravi Shankar, lead author of the study and associate professor of industrial engineering in the University's Swanson School of Engineering. "The underlying mechanism that allows the Venus flytrap to capture prey is slow. But because its internal structure is coupled to use elastic instability, a snapping action occurs, and this delivers the power to shut the trap quickly. A similar mechanism acts in the beak of the Hummingbird to help snap-up insects"

The research was performed by Shankar in collaboration with Timothy J. White of the Air Force Research Laboratory at Wright-Patterson Air Force Base and Matthew Smith, assistant professor of engineering at Hope College in Holland, Mich.

Focusing on this elastic instability, Shankar examined polymeric materials, prepared by researchers at the Air Force Research Laboratory, which demonstrated unprecedented actuation rates and output powers. With light from a hand-held laser pointer, the polymers generate high amounts of power to convert the light into mechanical work without any onboard power source or wiring. Specific functions would be pre-programmed into the material so that the device would function once exposed to a light source and controlled by changing the character of the light.

"As we look to real-world applications, you could activate a switch simply by shining light on it," Shankar says. "For example, you could develop soft machines such as stents or other biomedical devices that can be more adaptive and easily controlled. In a more complex mechanism, we could imagine a light-driven robotic or morphing structure, or microvehicles that would be more compact because you eliminate the need for an on-board power system. The work potential is built into the polymer itself and is triggered with light."

The study, titled "Contactless, photoinitiated snap-through in azobenzene-functionalized polymers," was published Oct. 30, 2013, in the early edition of the Proceedings of the National Academy of Sciences.
-end-
Shankar's research was enabled through an eight-week Air Force Office of Scientific Research Summer Faculty Fellowship.

University of Pittsburgh

Related Engineering Articles from Brightsurf:

Re-engineering antibodies for COVID-19
Catholic University of America researcher uses 'in silico' analysis to fast-track passive immunity

Next frontier in bacterial engineering
A new technique overcomes a serious hurdle in the field of bacterial design and engineering.

COVID-19 and the role of tissue engineering
Tissue engineering has a unique set of tools and technologies for developing preventive strategies, diagnostics, and treatments that can play an important role during the ongoing COVID-19 pandemic.

Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.

Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.

Reverse engineering the fireworks of life
An interdisciplinary team of Princeton researchers has successfully reverse engineered the components and sequence of events that lead to microtubule branching.

New method for engineering metabolic pathways
Two approaches provide a faster way to create enzymes and analyze their reactions, leading to the design of more complex molecules.

Engineering for high-speed devices
A research team from the University of Delaware has developed cutting-edge technology for photonics devices that could enable faster communications between phones and computers.

Breakthrough in blood vessel engineering
Growing functional blood vessel networks is no easy task. Previously, other groups have made networks that span millimeters in size.

Next-gen batteries possible with new engineering approach
Dramatically longer-lasting, faster-charging and safer lithium metal batteries may be possible, according to Penn State research, recently published in Nature Energy.

Read More: Engineering News and Engineering 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.