Ferroelectricity in odd- and even-numbered nylons

Abstract

The D–E hysteresis and switching time were measured as well as X-ray, FTIR and thermal analyses for as-quenched nylon 6 and cold-drawn nylon 11 after quenching. The maximum remanent polarization of the former was 58 mC/m2 and that of the latter was 52 mC/m2. Such ferroelectricity in nylon 6 was partly related with an exothermic anomaly in C P at 336 K and attributed to the independent dipole rotation in the nematic-type unstable structure with loose molecular packing and imperfect hydrogen bonding, while the intermolecular steric hindrance mainly affected the D–E hysteresis disappearance in the cold-drawn nylon 11. Such results indicated that the number of CH2 groups between adjacent amide groups in a nylon chain (even or odd: polar or non-polar property in a chain with all-trans conformation) was not the determining factor in the cause of the ferroelectric property of nylons.