If we’re ever going to get on top of the whole plastic waste problem, a partial solution may lie in substances that fix themselves when broken, instead of having to be discarded. With that in mind, many groups have been developing self-healing materials – and one of the latest functions like blood.
Led by Prof. Keivan Davami, a team at Texas’ Lamar University started with a liquid resin that polymerizes (hardens) when exposed to ultraviolet light. Utilizing a form of 3D printing known as laser-assisted stereolithography, the scientists were able to create simple objects in which most of that resin had been exposed to UV light, solidifying it, while small reservoirs of unexposed liquid resin remained trapped inside.
As long as those objects remain undamaged, the liquid stays contained. If the polymerized resin gets cracked, however, capillary action draws some of the liquid resin out. Once quickly exposed to an artificial UV light source, that liquid resin then polymerizes, sealing up the crack.
This is not unlike the manner in which blood escapes to the surface of an injury, healing it. It’s also similar to the way in which mucilage is drawn out to seal cuts in the pads of the prickly pear cactus.
Davami and colleagues are now developing the technology further, with an eye toward reducing the amount of light energy required for the polymerization to take place. Ultimately, they would like to see the material self-heal with no human intervention, utilizing ambient UV sources such as sunlight.
It is hoped that the material could eventually be used for items such as tools, eyeglass frames or even the soles of shoes.