Nanoparticles lock together to hold water in place for more than a month
|WARPED WATER A tiny ball of water holds its football shape for days because nanoparticles coating it lock together to trap it.|
Distorted droplets of water can hold their elongated shapes for weeks when surrounded by a thin layer of nanoparticles.
Researchers at the University of Massachusetts Amherst plunged water droplets loaded with plastic nanoparticles into a mix of oil and silicone polymer. Submerged in the slimy solution, the water’s nanoparticles floated to the edges of the droplets and interacted with the silicone polymer to form a detergent, which coated each ball of water. The researchers then flipped on an electrical current, which stretched the water droplets and their detergent layers into a football shape.
When researchers switched off the electricity, a water droplet without the coating would reform into a ball. But the nanoparticles in the detergent layer jammed together and kept the water trapped in place for over a month, the researchers report in the Oct. 25 Science. Caged droplets could one day encapsulate tiny chemical reactions or deliver drugs.
Image: A water droplet stretched by an electrical current (top) gets held in place by a soapy layer of plastic nanoparticles surrounding it. The nanoparticles maintain the droplet’s stretched shape for more than a month, until the water starts to evaporate.