Featured Research

from universities, journals, and other organizations

Intelligent Plastics Change Shape With Light

Date:
May 2, 2005
Source:
Massachusetts Institute Of Technology
Summary:
Picture a flower that opens when facing the sunlight. In work that mimics that sensitivity to light, an MIT engineer and his German colleagues have created the first plastics that can be deformed and temporarily fixed into shape by light.

A sample of "smart" plastic (a) is elongated and irradiated on the right-hand side with ultraviolet light, forming a temporary shape (b). Photos (c) and (d) show the plastic recovering its original shape after exposure to UV light of a different wavelength. Scale is in centimeters.
Credit: Photo GKSS Research Center

Picture a flower that opens when facing the sunlight. In work that mimics that sensitivity to light, an MIT engineer and his German colleagues have created the first plastics that can be deformed and temporarily fixed into shape by light.

These programmed materials change shape when struck by light at certain wavelengths and return to their original shapes when exposed to light of specific different wavelengths.

The discovery, to be reported in the April 14 issue of Nature, could have potential applications in a variety of fields, including minimally invasive surgery. Imagine, for example, a "string" of plastic that a doctor could thread into the body through a tiny incision. When activated by light via a fiber-optic probe, that slender string might change into a corkscrew-shaped stent for keeping blood vessels open.

What about staples that open at a flash, or paper clips that relax when you don't need them anymore? Again, light could do the job.

"This is really a new family of materials that can change from one shape to another by having light shined on them," said Institute Professor Robert Langer of MIT.

Langer co-authored the paper with Andreas Lendlein, Hongyan Jiang and Oliver Jünger. Lendlein, a former MIT visiting scientist, is institute director at the GKSS Research Center in Teltow, Germany. With Jiang and Jünger, he is also affiliated with the Institute for Technology and Development of Medical Devices at Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University in Germany.

Shape memory

Plastics with "shape-memory"--ones that change shape in response to a temperature increase--are well known. In 2001, Langer and Lendlein were the first to report biodegradable versions of these materials in the Proceedings of the National Academy of Sciences.

A year later, the researchers introduced thermoplastic, biodegradable shape-memory polymers and demonstrated a nifty medical application--a smart suture that ties itself into the perfect knot. That work was described in the journal Science; mnemoScience GmbH of Aachen, Germany, was developed to commercialize the discovery.

"Now instead of heat, we can induce the shape-memory effect in polymers with light," said Lendlein.

Key to the work: "molecular switches," or photosensitive groups that are grafted onto a permanent polymer network. The resulting photosensitive polymer film is then stretched with an external stress and illuminated with ultraviolet light of a certain wavelength. This prompts the molecular switches to crosslink, or bind one to another.

The result? When the light is switched off and the external stress released, the crosslinks remain, maintaining an elongated structure. Exposure to light of another wavelength cleaves the new bonds, allowing the material to spring back to its original shape.

The team notes that in addition to elongated films, a variety of other temporary shapes can be produced. For example, a spiral can be created by exposing only one side of the stretched sample to light. So "while the deformation is well-fixed for [the irradiated] side, the other side keeps its elasticity. As a result, one contracts much more than the other when the external stress is released, forming an arch or corkscrew spiral shape," the authors write.

The team has also shown that the temporary shapes are "very stable for long times even when heated to 50 degrees C."

"In our Nature paper, the basic principle of photo-induced shape-memory polymers is explained. We are currently developing medical and industrial applications using their photosensitivity," Lendlein said.

The work was funded in part by a BioFuture Award from the Bundesministerium für Bildung und Forschung, Germany, and a fellowship from the Alexander von Humboldt Foundation.

A version of this article appeared in the April 27, 2005 issue of MIT Tech Talk (Volume 49, Number 25).


Story Source:

The above story is based on materials provided by Massachusetts Institute Of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute Of Technology. "Intelligent Plastics Change Shape With Light." ScienceDaily. ScienceDaily, 2 May 2005. <www.sciencedaily.com/releases/2005/05/050502094533.htm>.
Massachusetts Institute Of Technology. (2005, May 2). Intelligent Plastics Change Shape With Light. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2005/05/050502094533.htm
Massachusetts Institute Of Technology. "Intelligent Plastics Change Shape With Light." ScienceDaily. www.sciencedaily.com/releases/2005/05/050502094533.htm (accessed October 22, 2014).

Share This



More Matter & Energy News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins