Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Making the invisible visible: Color-changing indicators highlight microscopic damage

15.01.2016

Damage developing in a material can be difficult to see until something breaks or fails. A new polymer damage indication system automatically highlights areas that are cracked, scratched or stressed, allowing engineers to address problem areas before they become more problematic.

The early warning system would be particularly useful in applications like petroleum pipelines, air and space transport, and automobiles - applications where one part's failure could have costly ramifications that are difficult to repair. Led by U. of I. materials science and engineering professor Nancy Sottos and aerospace engineering professor Scott White, the researchers published their work in the journal Advanced Materials.


When cracks form, microbeads embedded in the material break open and cause a chemical reaction that highlights the damaged area.

Image courtesy Nancy Sottos

"Polymers are susceptible to damage in the form of small cracks that are often difficult to detect. Even at small scales, crack damage can significantly compromise the integrity and functionality of polymer materials," Sottos said. "We developed a very simple but elegant material to autonomously indicate mechanical damage."

The researchers embedded tiny microcapsules of a pH-sensitive dye in an epoxy resin. If the polymer forms cracks or suffers a scratch, stress or fracture, the capsules break open. The dye reacts with the epoxy, causing a dramatic color change from light yellow to a bright red - no additional chemicals or activators required.

The deeper the scratch or crack, the more microcapsules are broken, and the more intense the color. This helps to assess the extent of the damage. Even so, tiny microscopic cracks of only 10 micrometers are enough to cause a color change, letting the user know that the material has lost some of its structural integrity.

""Detecting damage before significant corrosion or other problems can occur provides increased safety and reliability for coated structures and composites," White said. White and Sottos are affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I.

The researchers demonstrated that the damage indication system worked well for a variety of polymer materials that can be applied to coat different substrates including metals, polymers and glasses. They also found that the system has long-term stability - no microcapsule leaking to produce false positives, and no color fading.

In addition to averting unforeseen and costly failure, another economic advantage of the microcapsule system is the low cost, Sottos said.

"A polymer needs only to be 5 percent microcapsules to exhibit excellent damage indication ability," Sottos said. "It is cost effective to acquire this self-reporting ability."

Now, the researchers are exploring further applications for the indicator system, such as applying it to fiber-reinforced composites, as well as integrating it with the group's previous work in self-healing systems.

"We envision this self-reporting ability can be seamlessly combined with other functions such as self-healing and corrosion protection to both report and repair damage," Sottos said. "Work is in progress to combine the ability to detect new damage with self-healing functionality and a secondary indication that reveals that crack healing has occurred."

###

The BP International Centre for Advanced Materials supported this work. Postdoctoral researcher Wenle Li was the first author of the work, and graduate students Christopher Matthews, Michael Odarczenko and Ke Yang were co-authors.

Editor's notes: To reach Nancy Sottos, call 217-333-1041; email: n-sottos@illinois.edu. To reach Scott White, call 217-333-1077; email swhite@illinois.edu.

The paper "Autonomous Indication of Mechanical Damage in Polymeric Coatings" is available online at http://onlinelibrary.wiley.com/doi/10.1002/adma.201505214/full.

Media Contact

Liz Ahlberg
eahlberg@illinois.edu
217-244-1073

 @NewsAtIllinois

http://www.illinois.edu 

Liz Ahlberg | EurekAlert!

More articles from Materials Sciences:

nachricht Gelatine instead of forearm
19.04.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Computers create recipe for two new magnetic materials
18.04.2017 | Duke University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, 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

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>