Influence of the OH-group rotations on the natural electret effect (spontaneous dipole polarization) in methyl alcohol cryodeposits

We have investigated the generation of the elctric polarization in methyl alcohol cryocondensates during deposition of the layer onto a cold substrate of temperature within the range 90–175 K. Interestingly, an electric polarization only appears in the α-phase, below ∼158 K, but none at all in the β-phase above 158 K. We believe that the complete absence of a polarization effect above 158 K is related to the onset of free rotations of the OH-group at 158 K, the temperature of the λ-phase transformation. We expect that the films of the α-methanol which grow-up below Tλ are of high crystalline order. Also, the increase of the surface charge density observed on lowering the condensation temperature may perhaps be caused by an increasing orientation of the fully polarized microcrystallites below Tλ.