Water Interactions with Crystalline Polymers with Large Dipoles

Abstract

We compare the interactions of water with the ferroelectric copolymer poly(vinylidene fluoride (PVDF) – trifluoroethylene (TrFE)) and poly(methylvinylidenecyanide) (PMCV), a strongly dipole ordered polymer. At the microscopic scale, dipole interactions matter and affect the surface chemistry at these polymer surfaces, as does lattice strain caused by water absorption. Light polarization dependent photo-assisted thermal desorption helps demonstrate that water desorption from surface and bulk can be influenced by the formation of electronic metastable states. Changes in local dipole orientation and the formation of long lived metastable states affect the strength of the coupling between the dipoles of water molecules and the dipoles of the copolymer poly(vinylidene fluoride – trifluoroethylene) but these effects were not observed for poly(methylvinylidenecyanide).