By Manipulating Condensation Conditions, Researchers Create Room-Temperature Ice | Popular Science: "Frankdicksonite has the desired hexagonal structure, but the Spanish team found it to be a less-than-ideal ice-nucleating material. Except for when its structure has imperfections. When BaF2has surface defects, its ability to spur condensation greatly improves. At the point of the surface defects, water tends to form tiny two-dimensional icy patches even under normal ambient conditions.
The finding could swing open the door for a new kind of synthetic, environmentally friendly material that spurs ice formation at higher temperatures. The team is currently working on just such a material, with hopes of later creating what they call "intelligent surfaces" that can manipulate water in specific ways."