One-Dimensional Polarization Dynamics in Ferroelectric Polymers

Despite the realization of ferroelectricity in the δ-phase of poly(vinyleden difluoride) (PVDF) nearly four decades ago, the dynamics of polarization switching has not been studied yet. Here, we unravel the polarization switching mechanism as a one-dimensional process that is nucleated by a 90° rotation of a CH₂-CF₂ repeat unit, forming a kink with reversed dipole along the polymer chain. The kink subsequently propagates in time, yielding full polarization reversal along the chain while preserving TGTG' chain conformation. We show that the domain wall mobility in δ-phase PVDF is faster than both conventional ferroelectric β-phase PVDF and its copolymers with trifluoroethylene, P(VDF-TrFE). The switching time at infinite electric field for δ-phase PVDF is ten times faster and amounts to 500 ps. Fast switching dynamics combined with the low voltage operation and high thermal stability of polarization make δ-PVDF a suitable candidate for microelectronic applications.