Researchers in Japan have created sponge-like crystals that soak up gases and liquids, but repel water.
Compounds known as porous coordination polymers can store or separate different molecules from a mixture, and produce catalytic reactions within their pores. But the polymers often break down in water. Susumu Kitagawa and his colleagues at Kyoto University designed small organic molecules, which they combined to make a porous crystal. The material has a nanometre-scale corrugated outer surface, which repels water droplets but draws other liquids through it. A previous strategy to make porous crystals water-repellent has been to attach bulky molecules after the crystal is made, but this has the undesirable side effect of blocking the pores that gases and non-aqueous liquids are supposed to enter.
Angew. Chem. Int. Edn http://doi.org/f2sr5g (2014)