Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

'Retrospective Rubber' Remembers Its Old Identities

17.12.2007
Researchers at the University of Rochester have developed a shape-memory rubber that may enable applications as diverse as biomedical implants, conformal face-masks, self-sealing sutures, and "smart" labels.

The material, described in the journal Advanced Materials, forms a new class of shape-memory polymers, which are materials that can be stretched to a new shape and will stay in that form until heated, at which time they revert to their initial shape.

Unlike conventional shape-memory polymers, however, the new material is transparent, rubbery, and most importantly, engineers will be able to control the speed at which it returns to its original shape. Other shape memory polymers use crystallization to hold a temporary shape, which often makes them opaque, hard, and brittle in their frozen states, and this can limit their use.

"At higher temperatures the material stretches like a rubber band, but, at lower temperatures, it stiffens up," says Mitchell Anthamatten, assistant professor of chemical engineering and inventor of the material. "This property can be used to temporarily hold the material in a deformed shape; and its original shape can be recalled by heating. Imagine an optical lens that can be triggered to change shape, a face-mask that can fit any user, or a biomedical implant that changes shape slow enough for a surgical procedure."

The new rubber functions differently than conventional shape-memory materials by using "sticker groups"—hydrogen bonding groups that form temporary bonds. These sticker groups break and reform constantly. It's akin to tearing a net apart only to find that new knots have formed between different strands. When the material is stretched, new bonds form that hold the material, temporarily, in its deformed shape. Creating the rubber with different amounts of sticker groups controls the rate at which the rubber returns to its original shape. With this control, Anthamatten envisions applications that today's shape-memory polymers simply can't fulfill.

"The pressure at which you hold together a sutured wound determines a lot about how it will heal," says Anthamatten. "This polymer could be made into a thread that responds precisely to body temperature, tightening the sutures to the perfect pressure."

Anthamatten is currently investigating how dyes diffuse through his networks. "We expect the rate of dye diffusion to increase with temperatures," says Anthamatten. This property may enable "smart" labels that account for time and temperature and can inform customers when products are about to expire. "We may not always have to rely on the expiration date. What if our milk was not refrigerated properly? What if the air conditioner failed for some time at the pharmacy? People want to know that their products are fresh."

One aspect of the clear rubber that surprised Anthamatten was how easy it is to make. "It's ridiculously simple," he says, "and we're fascinated by how small modifications lead to major changes in how the material behaves."

Jonathan Sherwood | EurekAlert!
Further information:
http://www.rochester.edu

More articles from Materials Sciences:

nachricht Switched-on DNA
20.02.2017 | Arizona State University

nachricht Using a simple, scalable method, a material that can be used as a sensor is developed
15.02.2017 | University of the Basque Country

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>