Nanoparticles lock together to hold water in place for more than a month
Courtesy of Science/AAAS
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.
M. Cui, et al. Stabilizing liquid drops in nonequilibrium shapes by interfacial jamming of nanoparticles. Science. Vol. 342, October 25, 2013, p. 460. doi: 10.1126/science.1242852
A. Grant. Under magnet's sway, fluids form simple structures. Science News Online. July 18, 2013.