One-Dimensional Polarization Dynamics in Ferroelectric Polymers

Despite the realization of ferroelectricity in the delta-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 degrees 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 delta-phase PVDF is faster than both conventional ferroelectric beta-phase PVDF and its copolymers with trifluoroethylene, P(VDF-TrFE). The switching time at infinite electric field for delta-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 delta-PVDF a suitable candidate for microelectronic applications.