Materials that can fix themselves are becoming a reality able to fix large holes, small fissures and more.There are several ways for self healing to work and a number of materials which are currently working towards a self healing revolution. The first to look at is a the latest options for self healing polymers. These are plastic or fibre composites that when stressed release a a healing agent or reconnect on a chemical level. The is a lot emerging in this area but first it’s important to understand what processes make this possible and what the benefits and weaknesses are.
1. Capsule based healing is pockets of healing agents embedded in the material which crack open and mix when the materials is damaged helping repair the material, only work in the area that breaks once and can’t fix large holes.
2.Vascular systems pump fluids in to damaged areas, they require a liquid source and some method to pump the liquid but can in theory repair larger areas. They are good for larger area repair but require the channels to be maintained.
Vascular systems are perhaps the hardest to maintain of all the systems as the tubes require access and filling however they can draw on much larger reservoirs of material to fix damages than capsule based solutions. The self healing record was set in fixing a hole more than 3cm wide using to vascular tubes liquids were poured into the hole, while still in it’s infancy this could have serious implications later. The work was completed by Scott Whites group at the university of Illinois, find out more here.
3.Intrinsic healing is based within the polymer itself. The material has bonds that chemically reconnect and repairs damage if the material is brought in to contact with itself in the right conditions.
This form of healing is perhaps the most elusive healing and is found only in polymers. The make up of the plastic is so willing to make bonds with itself that it acts almost like a self adhesive, the materials shown above require a resin that interacts either with air or a setting agent to become solid. This is not needed in this material. More can found out about materials that can do this here.
[three_first] Self healing concrete works by having tiny pockets of bacteria which when exposed to water form limestone helping to seal the crack and stop erosion from weather and stress.
Some examples of self healing can be seen in self healing tires like the ‘Duraseal’ tire system (which has a number of competitors) which is present as a layer within the tire and provides an almost instant fix.
Researchers at the university of Bristol predict that planes of the future will have self healing wings to fix micro cracks. This will dramatically improve safety as micro cracks can lead to catastrophic failures down the line.