rtoz (2530056) writes Whenever there is a major spill of oil into water, the two tend to mix into a suspension of tiny droplets, called an "emulsion." It is extremely hard to separate them, and they can cause severe damage to ecosystems. Now, MIT researchers have discovered a new, inexpensive way of getting the two fluids apart again. This new approach uses membranes with hierarchical pore structures. The membranes combine a very thin layer of nanopores with a thicker layer of micropores to limit the passage of unwanted material while providing strength sufficient to withstand high pressure and throughput.