Topological Structure-Induced Piezoelectricity from the α-Phase Poly(Vinylidene Fluoride).

Area of Science:

• Materials Science
• Polymer Science
• Condensed Matter Physics

Background:

• Topologically polar structures offer unique emergent phenomena not found in traditional ferroelectric materials.
• Topological structures are rare in ferroelectric polymers compared to ferroelectric oxides.

Purpose of the Study:

• To demonstrate the creation of a meron-like topological polar structure in the non-polar α-phase poly(vinylidene fluoride) (PVDF).
• To investigate the formation mechanism and properties of this novel topological structure.

Main Methods:

• Combined experimental techniques including Kelvin probe force microscopy, second harmonic generation, and dielectric spectroscopy.
• Computational methods to reveal the formation of twisted lamellae and the resulting topological structure.
• Direct and converse piezoelectric measurements.

Main Results:

• Successfully created a meron-like topological polar structure in α-phase PVDF.
• Demonstrated non-zero polarization facilitated by strain in the topological structure.
• Confirmed piezoelectricity in the topological α-phase PVDF, correlating it with polarization and topological features.

Conclusions:

• This work presents a new method for creating polar topological structures in non-polar ferroelectric polymers.
• The findings enable the induction of symmetry-forbidden properties, such as piezoelectricity, in non-polar polymer phases.