F. Marlow et al., PYROELECTRIC EFFECTS ON MOLECULAR-SIEVE CRYSTALS LOADED WITH DIPOLE MOLECULES, Journal of physical chemistry, 98(47), 1994, pp. 12315-12319
The pyroelectric effects of dipolar guest molecules in molecular sieve
crystals have been studied for the first time. The measurements have
been done on assemblages of aligned crystals as well as on individual
single crystals of the aluminophosphate molecular sieve AlPO4-5 loaded
with p-nitroaniline (PNA). The PNA molecules form unidirectionally al
igned dipole chains in parallel molecular sieve channels. We found tha
t the PNA dipoles are oppositely directed in the two halves of a singl
e crystal, forming two macroscopic regions of opposite polarization. I
t is concluded that the preferred direction of the dipole chains in th
e channel is a result of the adsorption process of the molecules into
the channels.