Accordingly, Dr Lin and his colleagues tried to build up covalent bonds between the layers of a water-repellent, or hydrophobic, material called cellulose acetate butyrate, which is used to make water-resistant fabrics.

ECONOMIST: Monitor: Encouraging hydrophobia | The

They immersed films made of cellulose acetate butyrate in solutions of phenyl azido and silica (which is positively charged) and phenyl azido and poly-allylamine hydrochloride (which is negatively charged).

ECONOMIST: Monitor: Encouraging hydrophobia | The