Ferroelectric behaviour of α-nylon 11

Measurements of the dielectric constant and pyroelectric coefficient of alpha -nylon 11 have been carried out in the temperature range from -20 degrees C to 120 degrees C. The temperature dependence of both the dielectric constant and pyroelectric coefficient was found to correlate with an anomalous temperature dependence of the thermal expansion coefficient determined for the polar direction in the alpha crystal. The results are discussed in terms of a diffuse ferroelectric-paraelectric transition.