J. Phys. Chem. B doi:10.1021/jp073870c (2008)

Ice can generate a voltage when heated or cooled, say Richard Bell at Pennsylvania State University in Altoona, James Cowin of Pacific Northwest National Laboratory in Richland, Washington, and their co-workers. The trick is to deposit ions at -113 °C onto a 1-micrometre-thick ice film, thereby charging the surface of the film and rotating its water molecules, which become locked in position when the film is later cooled.

Normally, water molecules are randomly oriented in ice. Each one has an asymmetrical distribution of positive and negative charge that could create a voltage were many water molecules to become frozen in alignment. Cowin's team's method achieves a voltage as large as those generated by commercial materials and that varies steeply and reversibly with temperature.

The same process could cause an electrostatic attraction between icy grains exposed to cosmic rays in space, promoting their aggregation into proto-planetary lumps.