nano zinc oxide sunblock

What is nanotechnology? Chemists often get upset when the adjective nano is used to describe something because all chemistry takes place at the nanoscale. People have been using zinc oxide as a sunblock for decades. Until recently, the zinc particles that made up the sunblock had a rather large diameter, and that gave the sunblocks a pasty white appearance. Recently, several companies have begun marketing sunblocks that use zinc oxide particles that are less than a hundred nanometers across. While they have the same chemical composition as the old sunblocks, the particles have been processed into a smaller size, and this makes them clear. Some may argue that this is too primitive to be considered nanotechnology, and yet it relies on the ability to control the structure of something at the nanoscale and provides an unambiguous benefit.