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.
William, thanks for your comment. I agree with you about this not being likely for consumer-grade use. We addressed this issue earlier in the thread: since this is not close to commercial development yet, price and cost differentials are unknown. But self-healing plastics like this one--which unusually can self-heal multiple times--multiply the life of the object several times. Less plastic gets used during that time, so the COO to manufacturers would be lower than buying it once. 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 or medical products.
It would be quite useful to know some of the more common materials propertiies of this self healing material, such as strength, stiffness, and temperature ratings, and that all important property, PRICE. My guess is that it would never be found in consumer goods evenif the cost were half that of styrene regrind. It appears that many consumer goods have avery intentional low quality level, so that they would be replaced every few months.
ChasChas, thanks for that comment. I agree with you. I've reported on several other experimental materials that seem to be moving toward intelligence, some of them via nanotechnology, and many of them based on shifts in electrical charge.
Nadine, thanks for the clarification. Since this material is aimed at self-repairing surface damage, I don't think it's designed for implants. But that's an interesting idea. There are many biocompatible plastics made for that application, and designing one of those to be self-healing would be a good PhD project.
Ann: I'm thinkiing specifically about joint replacement. I had the honor to attend an orthopaedic surgeons conference a few months ago. The technology is very interesting and has been making slow advances, especially in hip replacements. Even temperature and PH changes would be problematic for spine, knee and hip replacements.
But, it may cause less trauma than entirely replacing the unit.
Meanwhile, these new plastics are only a drop in the huge bucket of the amount of plastics we consume. So extending the life of non-recyclable, non-compostable plastics by reusing them helps keep them out of the landfill.
Nadine, intense light is one possible exposure mechanism--the article also mentions changes in temperature or pH. I'm not sure why strong light would be a problem for an implant, since an implant is usually kept away from light. Can you tell us more about what you mean?
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.