Urban pointed out that biological systems that can repair themselves may do so by either visible or invisible means. "Some we can see, like the skin healing and new bark forming in cuts on a tree trunk," he said in a press release.
"Some are invisible, but help keep us alive and healthy, like the self-repair system that DNA uses to fix genetic damage to genes."
The team, at the University of Mississippi's Urban Research Group, has worked on similar technology for several years. It has developed plastics with small molecular links that span the long chains of polymer's component chemicals.
The links break and change shape when the polymer is scratched or cracked. Modifying the links resulted in a visible color change when they change shape, forming a red blotch around the defect. (Watch a video of an accelerated similar self-repairing process, which doesn't change color first, here.) The links reform when temperature or pH changes, or when in the presence of ordinary sunlight or visible light from a light bulb.
Urban said that automobile fenders made of the new material that have become scratched could be repaired by being exposed to intense light. Structural components of aircraft could turn red where they have become cracked as a warning of damage. That would give engineers the choice of fixing the damage or completely replacing the component. He also cited several applications for battlefield weapons systems.
The team, which received funding for the project from the US Department of Defense, is currently working on incorporating the technology into plastics that can withstand high temperatures.
Ann, this is interesting. One thing I was thinking as I read this, though. One of the attributes of plastics is their low cost. One of the benefits of that is that you would replace the part rather than fix it. Taking that into consideration, how does the cost of this type of plastic compare to conventional plastics? I realize this is not in production yet.
Good question naperlou. You're right, this is not close to commercial development yet, so cost differentials are unknown. But since a self-healing plastic like this one--which unusually can self-heal multiple times--prolongs the life of the object many times, it means using less of it during that time. That cost amortization, as well as the benefits of not throwing away the object, implies that the COO to manufacturers would be lower than buying it once. I think the point here is that it's not aimed at high-volume, low-cost throwaway applications, but ones where continued use of a high-value product is important, such as military products or structural components.
Thanks for the great article. naperlou makes a good point but I think the evolution of materials is moving away from convenience and towards true sustainability. The throw away culture we created in the early 20th century can't continue. Textiles made from pre and post consumer materials like milk fiber and wood bark were put on the shelf for the new thing--nylon. Now, we're dusting off that old research.
This sounds good but impractical for now. The cost and application make it very limited. if something like this could exist in medical devices, I'd be very impressed.
Looking forard to hearing more about this in the future.
Interesting story, Ann. I'm wondering if there are certain types of material damage that cannot be self-repaired. Your story mentions scratches. What about deformation caused by bending, particularly beyond the elastic limit of the material? If it could self-repair in those situations, it seems like it could be used in structural applications.
Nadine, I think you're right about moving toward sustainability. But that's exactly what this could provide. Sustainable materials includes those made from greener materials (with lots of discussion about what that means), with greener processes (ditto), which can be recycled in various ways, and/or which can be used longer before being thrown away (or before being recycled). Sustainable materials can fulfill one or more of those 4 categories. This material can be classified in the last category.
We don't yet know how much more this plastic would cost, although it's being targeted at higher-priced apps, that's true. But after being developed for commercial production with those R&D dollars, it could then be extended and adapted to lower-cost apps, like medical. This is a common roadmap for new technologies.
@Ann-I completely agree. Cost is a major factor for mass market appeal. But, if the cost is the same or just slightly higher, it can fit into the general trend towards sustainability.
The article says that the plastic has to be exposed to intense light to heal itself. That's limiting for most medical implants but could be usuful in sports safety and performance enhancement equipment.
Ann, I liked your point about new medical applications for this technology. Many medical plastic components are constantly exposed to harsh sterilization chemicals during regular cleaning and maintenance procedures. If this self-healing process also works after a chemical exposure, it could be an interesting advancement for medical equipment designers.
Ann, first of all plastic is not an environmental friendly material. So most of the countries are trying either to reduce or ban the use of plastics. In such a scenario, what's the relevance of these types of thermoplastics? Is it something in an environmental friendly way?
Many of the new adhesives we're featuring in this slideshow are for use in automotive and other transportation applications. The rest of these new products are for a wide variety of applications including aviation, aerospace, electrical motors, electronics, industrial, and semiconductors.
A Columbia University team working on molecular-scale nano-robots with moving parts has run into wear-and-tear issues. They've become the first team to observe in detail and quantify this process, and are devising coping strategies by observing how living cells prevent aging.
Many of the new materials on display at MD&M West were developed to be strong, tough replacements for metal parts in different kinds of medical equipment: IV poles, connectors for medical devices, medical device trays, and torque-applying instruments for orthopedic surgery. Others are made for close contact with patients.
New sensor technology integrates sensors, traces, and electronics into a smart fabric for wearables that measures more dimensions -- force, location, size, twist, bend, stretch, and motion -- and displays data in 3D maps.
As we saw on the show floor this week at the Pacific Design & Manufacturing and co-located events in Anaheim, Calif., 3D printing is contributing to distributed manufacturing and being reinvented by engineers for their own needs. Meanwhile, new fasteners are appearing for wearable consumer and medical devices and Baxter Robot has another software upgrade.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.