Effect of annealing on the ferroelectric behavior of nylon ‐ 11 and nylon ‐ 7

Abstract

We have discovered recently that melt‐quenched and cold‐drawn Nylon ‐ 11 films exhibit very clear ferroelectric hysteresis behavior. In the present study, a remanent polarization as high as 86 mC/m2 has been found in Nylon ‐ 7 samples; this is significantly higher than that usually observed in poly (vinylidene fluoride) films. The effect of annealing on the electric displacement versus electric field characteristics of both Nylon ‐ 11 and Nylon ‐ 7 films have been studied and show an increased coercive field (62 to 115 MV/m for Nylon ‐ 11 and 79 to 97 MV/m for Nylon ‐ 7) and a decreased remanent polarization (51 to 17.3 mC/m2 for Nylon ‐ 11 and 86 to 70.5 mC/m2 for Nylon ‐ 7) with increasing annealing temperature from 25 to 145°C.

Ferroelectric polarization mechanisms in nylon 11

“…The electric displacement D and applied field E hysteresis studies carried out previously clearly indicate that Nylon 11 films, prepared by quenching and cold-drawing, behave as a ferroelectric material (11,12). Further, previous studies also showed that annealing prior to poling significantly decreased the spacing between hydrogen bonded sheets and also that this annealed structure showed a reduced reorientation of dipoles with These results clearly suggest that dipole reorientation in Nylon 11 films is inhibited by annealing.…”

“…This new class of ferroelectric polymer, the odd-numbered nylons, have a crystal structure based on the packing of hydrogen-bonded sheets (14,15). From previous studies (12,16), and the lack of observed ferroelectricity in the even-numbered nylons, it is apparent that the ferroelectric response originates in the crystalline regions. Both the hydrocarbon sections, as well as the amide groups play an important role in the ferroelectric behavior of these semicrystalline nylons.…”

“…A number of studies of piezoelectricity in the odd-numbered nylons has culminated recently in the demonstration of clear hysteresis loops of electric displacement D and applied electric field E, typical of ferroelectric materials, for Nylon 11 and Nylon 7 films prepared by quenching from the melt, followed by cold drawing (11)(12)(13). This new class of ferroelectric polymer, the odd-numbered nylons, have a crystal structure based on the packing of hydrogen-bonded sheets (14,15).…”

Unique Ferroelectricity and Structure of Nylon 39 Induced by an Electric Field

“…[1][2][3][4][5][6][7][8][9][10] Nylons synthesized by the polycondensation of dicarbonic acids with odd numbers of carbon atoms and diamines composed of odd-numbered carbon atoms have ferroelectricity because of their structures formed due to the hydrogen bonds between polymer chains. Scheinbeim et al [11][12][13][14][15] detected the ferroelectricity of nylon 7 prepared by quenching and drawing at low temperature. Nylon 7 is forced to form distorted structures to form hydrogen bonds [3], and the samples with disordered structures prepared by quenching can be made ferroelectric by applying an electric field.…”

Novel Primary Dispersion in Viscoelastic Behavior of Ferroelectric Nylon 6

“…2,3 The authors reported that the amorphous nylon 6 thin film prepared by quenching from the melt showed the D-E hysteresis phenomena. 1 It was suggested by Yanagisawa et al 4 that packing of molecular chains in the asquenched ferroelectric nylon 6 is looser (density is less than 1.00 g/cm 3 : amorphous A) than that in the paraelectric amorphous phase (density is 1.09 g/cm 3 : 5 amorphous C) included in the slow-cooled nylon 6 (partly crystallized). However, the structural nature of the amorphous A and the precise mechanism of the D-E hysteresis appearance seem to be still unclear.…”