The idea of using nano-coating to maintain a surface clean is not new. There are now in commerce glass panes (for windows but also for solar panel) that are coated by nano structures ensuring a self cleaning surface.
However, researchers at RMIT University in Australia have gone a step further finding a way to use nano-structures to coat textiles. Specifically, they have found a way to cover cotton fibres with copper and silver nanoparticles.
When exposed to sun light these nano-structures transfer the visible light energy to electrons via localised surface plasmon resonance, a complex name to indicate that electrons on the surface of the material bounce one on the other in a synchronous way harvesting energy.
These high energy electrons activate chemical reactions that break organic chains, the one that stain your towels and shirts..., and act like very powerful washing machines keeping the surface clean.
The cotton fibres of the textile are particularly good at capturing light, hence the nano-coating receives plenty of it and can be very effective.
However, it is not time, yet, to throw away your washing machine. It will take quite some time before moving this lab result into something that is practical and economically sustainable.