Achieving Relaxor Ferroelectric Behavior in Nylon-based Polymers

High dielectric constant polymers, exhibiting relaxor ferroelectric behaviors (i.e., slim single and double hysteresis loops), are attractive for high energy density and low loss dielectric applications. Utilizing the principle of nanosized ferroelectric domains (nanodomains), this work has designed and developed novel relaxor ferroelectric polyamides (PAs or nylons) as an alternative to the high-cost and difficult-to-synthesize poly(vinylidene fluoride) (PVDF) based relaxor ferroelectric polymers. For nylon-based polymers, the mesomorphic crystalline structure is important for the electric field-induced ferroelectricity. First, slim double hysteresis loop behavior can be achieved for even-numbered nylons at high temperatures. Second, the slim single hysteresis loop behavior can be achieved in PA terpolymers at high temperatures. Pathways to achieve relaxor ferroelectric behaviors for nylon-based polymers are discussed and compared with those for PVDF-based polymers. The knowledge obtained from this study can inspire potential applications for nylon polymers in advanced electrical and power applications.