Spontaneous Polarization of Cryo-Deposited Films for Five Normal Saturated Monohydroxy Alcohols, CHOH, = 1-5.

Vapor-deposited films of neutral polar molecules on cold surfaces exhibit spontaneous electric polarization across the faces of the film. We deposited known amounts of the first five members of the normal monohydroxy alcohols at substrate temperatures in the range of 30-130 K. It is known that voltages measured are proportional to film thickness and that the effect is substrate-independent.

Spontaneous polarization of vapor-deposited 1-butanol films and its dependence on temperature.

Films of 1-butanol were vapor deposited under vacuum conditions at cryogenic temperatures on a polycrystalline platinum foil. Kelvin probe measurements showed the generation of a large negative voltage on the vacuum side of the film relative to its back side in contact with the platinum foil. Voltages across vapor deposited films, which are known to require molecules with an electric dipole moment, were confirmed to be proportional to the amount of gas deposited at a given temperature.