Electric activity in rigid rod-like polymer, poly(β-hydroxybutyrate)

Poly(β-hydroxybutrate) (PHB), one of the most promising environmental friendly polymers, was found to be rich in electric activities. Our experimental results demonstrated that the PHB exhibited ferroelectric behavior, as well as pyroelectric behavior. A remanent polarization of the PHB system was as large as 67 mC/m2 at 100 °C from a displacement-field hysteresis loop, while it possessed pyroelectric coefficient as large as 20 μC/m2 K after a poling procedure. The remanent polarization exhibited unique temperature dependence and it increased rapidly at the temperatures higher than 80 °C. The polarization due to the ester dipole ordering is likely formed in the direction perpendicular to the helical axis.