Achieving Relaxor Ferroelectric-like Behavior in Nylon Random Copolymers and Terpolymers

Abstract

High dielectric constant polymers, exhibiting relaxor ferroelectric (RFE) behaviors (i.e., slim single and double hysteresis loops, SHLs and DHLs), are attractive for high energy density and low loss dielectric applications. Utilizing the principle of nanosized ferroelectric domains (nanodomains), this study has designed and developed novel RFE-like polyamides (PAs) based on 11-aminoundecanoic acid, 12-aminododecanoic acid, and N-methyl-11-aminoundecanoic acid (NM11) as an alternative to the high-cost and difficult-to-synthesize poly(vinylidene fluoride) (PVDF)-based RFE polymers. In the first attempt, quenched and stretched (QS) PA(11-co-12) copolymers exhibited enhanced ferroelectricity as compared with either nylon-11 or nylon-12. Although relatively narrow hysteresis loops could be achieved at 75 °C, the hydrogen-bonding interaction was not weak enough to induce nanodomains in the nylon copolymers. To further reduce the hydrogen-bonding interaction and achieve nanodomains, a PA(11-co-12-co-NM11) 30/60...