Piezoelectricity

Organic chemistry

Pyroelectricity

Fluoride

Crystallography

Engineering

Dielectric

Polarizability

Physical chemistry

Composite material

Inorganic chemistry

Chemistry

Materials science

Programming language

Polarization (electrochemistry)

Molecule

Computer science

Phase (matter)

Crystallinity

Amorphous solid

Crystal (programming language)

Poling

Chemical engineering

Optoelectronics

Polymer

Ferroelectricity

Nature Communications

Piezoelectric polymers hold great potential for various electromechanical applications, but only show low performance, with | d 33 | &lt; 30 pC/N. We prepare a highly piezoelectric polymer ( d 33 = −62 pC/N) based on a biaxially oriented poly(vinylidene fluoride) (BOPVDF, crystallinity = 0.52). After unidirectional poling, macroscopically aligned samples with pure β crystals are achieved, which show a high spontaneous polarization ( P s ) of 140 mC/m 2 . Given the theoretical limit of P s,β = 188 mC/m 2 for the neat β crystal, the high P s cannot be explained by the crystalline-amorphous two-phase model (i.e., P s,β = 270 mC/m 2 ). Instead, we deduce that a significant amount (at least 0.25) of an oriented amorphous fraction (OAF) must be present between these two phases. Experimental data suggest that the mobile OAF resulted in the negative and high d 33 for the poled BOPVDF. The plausibility of this conclusion is supported by molecular dynamics simulations.

Enhanced piezoelectricity from highly polarizable oriented amorphous fractions in biaxially oriented poly(vinylidene fluoride) with pure β crystals