Direct mapping of local polar distortion in relaxor ferroelectric polymers by using atomic force microscope infrared-spectroscopy

Relaxor ferroelectrics are a well-known disordered system whereas the local polar structure at nanoscale is essential to understanding of their striking properties. Here we use atomic force microscope infrared-spectroscopy (AFM-IR) to provide direct mapping of local conformational configuration in relaxor ferroelectric polymers [Y. Liu et al, Nature Mater. 2020, 19, 1169]. We found that chemical pattern of all-trans conformation-representing the ferroelectric β phase-is strongly spatially dependent in relaxor polymers in contrast to normal ferroelectric composition with a nearly homogenous chemical pattern. Moreover, our local spectra clearly reveal the strong position-dependence of local chain conformation in relaxor ferroelectric polymers. We show that this feature of relaxors revealed by AFM-IR technique is independent of measurement mode demonstrating that chain conformational disorder is inherent to relaxor ferroelectric polymers.