Scientists solve sticky problem of soap dregs

THE days of struggling to squeeze out the last dregs of shampoo or washingup liquid could soon be over.

Scientists in the US have developed a nanoparticle coating for plastic bottles that allows soap products to flow more freely. It means that every drop of liquid soap, shampoo or laundry detergent can be removed and none wasted.

Technology already existed to help food products pour out of containers, but soap is a much stickier problem.

Prof Bharat Bhushan, the lead scientist, from Ohio State University, said: “Compared to soaps, getting ketchup out of a bottle is trivial.”

His team has developed a way of lining plastic bottles with microscopic Yshaped structures that cradle droplets of soap above tiny air pockets.

As a result, the soap never actually touches the sides of the bottle.

Instead of spreading out, the soap droplets form beads and roll off the surface.

The Y structures are built up using much smaller nanoparticles made from silica or quartz, an ingredient in glass.

Prof Bhushan said: “It’s what you’d call a first-world problem, right? ‘I can’t get all of the shampoo to come out of the bottle.’ But manufacturers are really interested in this, because they make billions of bottles that end up in the garbage with product still in them.”

Before plastic bottles can be recycled, they have to be rinsed completely clean.