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 A remote control for neurons
04.06.2020 | College of Engineering, Carnegie Mellon University

nachricht Smart textiles made possible by flexible transmission lines
03.06.2020 | Ecole Polytechnique Fédérale de Lausanne

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Restoring vision by gene therapy

Latest scientific findings give hope for people with incurable retinal degeneration

Humans rely dominantly on their eyesight. Losing vision means not being able to read, recognize faces or find objects. Macular degeneration is one of the major...

Im Focus: Small Protein, Big Impact

In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.

Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...

Im Focus: K-State study reveals asymmetry in spin directions of galaxies

Research also suggests the early universe could have been spinning

An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...

Im Focus: New measurement exacerbates old problem

Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.

Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New image of a cancer-related enzyme in action helps explain gene regulation

05.06.2020 | Life Sciences

Silicon 'neurons' may add a new dimension to computer processors

05.06.2020 | Physics and Astronomy

Protecting the Neuronal Architecture

05.06.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>