Scientists have discovered a new polymer that could be repaired with nothing more than UV light. The material is a metallosupramolecular polymer, a rubbery substance with bits of metal throughout. It's made of molecular chains which naturally latch together to form bigger ones, in a stable lattice. When damaged, this matrix of chains is disturbed — and that's when the cunning part comes in. The material can absorb UV light, and turn it into heat, which allows the chains to disassemble, flow around the damage, and when the light is turned off, the chains re-assemble.
There are existing self-healing polymers, but they require direct heating to repair damage. The advantage to this new material is that the UV light can be beamed at an extremely localized area, and even repair it while it's bearing a load.
Another day, another step closer to the T-1000.