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Ferroelectric and piezoelectric behavior in odd‐odd polyamide 11,11 are successfully detected for the first time. The maximum coercive field (Ec) of 90 MV/m, and a remnant polarization (Pr) of 40 mC/m2 are obtained at room temperature. A piezoelectric strain coefficient (d33) value as high as −3.9 pC/N has been found in stretched polyamide 11,11 film. The structural change of samples before and after poling is investigated by wide‐angle X‐ray diffraction patterns, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The results indicate that the nature of the ferroelectricity originates from amide group dipoles in the γ‐form crystal regions. Hysteresis behavior appears to result from the crystallites reversal mechanism. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1094–1099

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Piezoelectricity and ferroelectricity in odd-odd nylon 11,11 and nylon 13,13 are detected. The results indicate that the γ-phase is responsible for the high piezoelectric and ferroelectric response. The piezoelectric strain coefficient, d33, as high as −3.9 and −4.1 pC/N is obtained at room temperature for stretched nylon 11,11 and nylon 13,13 films, respectively. The coercive electric field, Ec, values of about 55 and 88 MV/m are obtained for nylon 11,11 and nylon 13,13 films, respectively. And a remanent polarization, Pr, about 40 mC/m2 has been found in both films. Compared with nylon 11,11, the lower coercive electric field (Ec) in nylon 13,13 is attributed to its longer alkyl chains. These odd-odd nylons have the potential in electroactive applications.