Certainly no more unemployment than was caused by the invention of automobile farm equipment, but I think most people come down in favor of that.

Dirt and grit still accumulates somewhere. Bins still need to be emptied.

And by new jobs spraying coating.

Not necessary unemployment, maybe conversion. Perhaps cleaning industries will take care of providing and deploying hydrophobic substances in toilets, firms, public services etc.

Or maybe as you suggest it will create a completly new market. It depends entirely on the ability of these companies to move forward.