Materials science: Pointing the way to cleaner waters

A cactus-inspired method for removing oil droplets from water is reported this week in Nature Communications. Based on the ability of cactus needles to pull tiny drops of water from the air, researchers built artificial spikes that catch tiny oil droplets in water - a creation that could have implications for cleaning oil spills in the future.

With so much environmental damage caused by oil spills, ways to easily separate oil from water are in increasing demand. Lei Jiang and co-workers observed how cacti spines condense moisture from air, helping to keep the plant hydrated in desert environments. They reasoned that artificial spikes could do a similar job for oil droplets in water, and designed arrays of copper spikes that act as highly efficient oil absorbents. The advantage of the method reported in this work is that it can be used to trap microscopic sized drops that could be missed by conventional separation technologies.