Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Repeated Self-Healing Now Possible in Composite Materials

16.04.2014

Researchers at the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign have created a 3D vascular system that allows for high-performance composite materials such as fiberglass to heal autonomously, and repeatedly.

Internal damage in fiber-reinforced composites, materials used in structures of modern airplanes and automobiles, is difficult to detect and nearly impossible to repair by conventional methods. A small, internal crack can quickly develop into irreversible damage from delamination, a process in which the layers separate. This remains one of the most significant factors limiting more widespread use of composite materials.


3D microvascular networks for self-healing composites: Researchers were able to achieve more effective self-healing with the herringbone vascular network (top) over a parallel design (bottom), evidenced by the increased mixing (orange-yellow) of individual healing agents (red and green) across a fracture surface.

However, fiber-composite materials can now heal autonomously through a new self-healing system, developed by researchers in the Beckman Institute’s Autonomous Materials Systems (AMS) Group at the University of Illinois at Urbana-Champaign, led by professors Nancy Sottos, Scott White, and Jeff Moore. 

Sottos, White, Moore, and their team created 3D vascular networks—patterns of microchannels filled with healing chemistries—that thread through a fiber-reinforced composite. When damage occurs, the networks within the material break apart and allow the healing chemistries to mix and polymerize, autonomously healing the material, over multiple cycles. These results were detailed in a paper titled “Continuous self-healing life cycle in vascularized structural composites,” published in Advanced Materials.

“This is the first demonstration of repeated healing in a fiber-reinforced composite system,” said Scott White, aerospace engineering professor and co-corresponding author. “Self-healing has been done before in polymers with different techniques and networks, but they couldn’t be translated to fiber-reinforced composites. The missing link was the development of the vascularization technique.”

“The beauty of this self-healing approach is, we don't have to probe the structure and say, this is where the damage occurred and then repair it ourselves,” said Jason Patrick, a Ph.D. candidate in civil engineering and lead author.  

The vasculature within the system integrates dual networks that are isolated from one other. Two liquid healing agents (an epoxy resin and hardener) are sequestered in two different microchannel networks. 

“When a fracture occurs, this ruptures the separate networks of healing agents, automatically releasing them into the crack plane—akin to a bleeding cut,” Patrick said. “As they come into contact with one another in situ, or within the material, they polymerize to essentially form a structural glue in the damage zone. We tested this over multiple cycles and all cracks healed successfully at nearly 100 percent efficiency.”

Notably, the vascular networks within the structure are not straight lines. In order for the healing agents to combine effectively after being released within the crack, the vessels were overlapped to further promote mixing of the liquids, which both have a consistency similar to maple syrup.

Fiberglass and other composite materials are widely used in aerospace, automotive, naval, civil, and even sporting goods because of their high strength-to-weight ratio—they pack a lot of structural strength into a very lean package. However, because the woven laminates are stacked in layers, it is easier for the structure to separate between the layers, making this self-healing system a promising solution to a long-standing problem and greatly extending their lifetime and reliability.

“Additionally, creating the vasculature integrates seamlessly with typical manufacturing processes of polymer composites, making it a strong candidate for commercial use,” said Nancy Sottos, materials science and engineering professor and co-corresponding author. 

Fiber-composite laminates are constructed by weaving and stacking multiple layers of reinforcing fabric, which are then co-infused with a binding polymer resin. Using that same process, the researchers stitched in a sort of fishing line, made from a bio-friendly polymer and coined “sacrificial fiber,” within the composite. Once the composite was fabricated, the entire system was heated to melt and evaporate the sacrificial fibers, leaving behind hollow microchannels, which became the vasculature for the self-healing system.

This work was supported by the Air Force Office of Scientific Research, the Department of Homeland Security Center of Excellence for Explosives Detection, Mitigation, and Response, and the Army Research Laboratory. Jeff Moore, Kevin Hart, Brett Krull, and Charles Diesendruck were also co-authors on the paper.

August Cassens | Eurek Alert!
Further information:
http://beckman.illinois.edu/news/2014/04/self-healing-composites

More articles from Materials Sciences:

nachricht “Seeing” molecular interactions could give boost to organic electronics
03.08.2015 | Institute for Integrated Cell-Material Sciences at Kyoto University

nachricht Controlling phase changes in solids
29.07.2015 | ICFO-The Institute of Photonic Sciences

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Glaciers melt faster than ever

Glacier decline in the first decade of the 21st century has reached a historical record, since the onset of direct observations. Glacier melt is a global phenomenon and will continue even without further climate change. This is shown in the latest study by the World Glacier Monitoring Service under the lead of the University of Zurich, Switzerland.

The World Glacier Monitoring Service, domiciled at the University of Zurich, has compiled worldwide data on glacier changes for more than 120 years. Together...

Im Focus: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

NASA's RapidScat sees Hurricane Guillermo's strongest winds on western side

04.08.2015 | Earth Sciences

NASA sees heavy rainfall in Super Typhoon Soudelor

04.08.2015 | Earth Sciences

Study calculates the speed of ice formation

04.08.2015 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>