P. A. Jacobson

Water absorption and dielectric changes in crystalline poly(vinylidene fluoride-trifluoroethylene) copolymer films

Crystalline Langmuir–Blodgett copolymer films of vinylidene fluoride with trifluoroethylene (70%:30% and 80%:20%) absorb water. Water absorption is accompanied by film swelling, as indicated by an increase in lattice spacing, sometimes by as much as 5%. This water absorption, between 0 and 40 °C, is a result of intercalation or occupation of interstitial sites between the layers of the film, not just water molecules filling voids and defect sites alone. An increase in the film capacitance is observed, although the polymer chains retain all trans configuration of the ferroelectric phase.

The elimination of the influence of ambient environmental effects on the structure of `inert' polymers

The construction and use of a vacuum chamber suitable for conventional X-ray diffraction has revealed the influence of the ambient environment, including moisture, on the bulk structure of very thin polymer films. It is concluded that studies of thin film organic systems, even those thought not to be perturbed by ambient water vapor and other contaminants, may benefit from undertaking some studies in such small sample vacuum chambers.

Angle resolved thermal desorption studies for poly(methylvinylidene cyanide) and poly(vinylidenefluoride trifluoroethylene)

We compare water adsorption and desorption on ferroelectric copolymer poly(vinylidene fluoride-trifluoroethylene), and the dipole ordered polymer poly(methylvinylidene cyanide). The angle-resolved thermal desorption spectra prove that the absorbed water species interacts more strongly with poly(vinylidene fluoride-trifluoroethylene) than with poly(methylvinylidene cyanide). The angle resolved thermal desorption spectra shows large deviations from the cos θ distribution for light illuminated poly(vinylidene fluoride-trifluoroethylene). Water desorption from poly(methylvinylidene cyanide) deviates from the cos θ distribution without illumination.