Scientists at Ohio State University have invented a plastic on which soap doesn't stick. In fact, the soap doesnt even really touch the plastic, being held aloft on a pillow of air that lies between the contents of the bottle of liquid soap and the polypropylene walls of the bottle.
The trick: Y-shaped nano-structures made of silica or quartz - a material found in glass. Each Y-shape overhangs the one below, creating tiny air pockets. Unlike water, which prefers to cling to other molecules of water and will achieve enough weight to roll down towards the bottom of a bottle stored with its squeeze-hole end pointed down, soap prefers to cling to the plastic and will not leave the side of the bottle on the strength of gravity alone.
The technology can be seen in the video below, including a demonstration of the flow of liquid soap over a traditional surface and the new nano-plastic.
As a technological solution, this invention has several things going for it. It is cheaper than other alternatives under development. It is reported to actually improve the recyclability of the plastics because the soap surfactants disrupt the recycling and must be washed off of the plastics before processing.
But it begs one huge question: does this mean most people don't know how to get the last bit of soap out of their plastic bottles already? It is really not much of a trick. Just add water, shake well, and use the diluted soapy solution the same way you would use the soap, without the need to mix more water in during the washing as one usually would with the concentrate. After one or two cycles of diluted-soap use, a final rinse will leave the bottle clean, while discharging a minimum of unused chemicals to the environment.
So what do you think? Do you get the soap out before you toss your empty bottles? Or do you already use plastic-free soaps?