Synthesis and Solution Processing of Nylon‐5 Ferroelectric Thin Films: The Renaissance of Odd‐Nylons?

Abstract

Among odd‐nylons, nylon‐5 exhibits the highest remanent polarization and is thus a desirable material for many applications of ferroelectric polymers. However, nylon‐5 has never been used as a ferroelectric material, because the synthesis of nylon‐5 and its processing into thin films are challenging. This work revisits the synthesis of nylon‐5 via anionic ring opening polymerization (AROP) and studies the effect of reaction time and scale‐up on (i) molecular weight (Mn), (ii) melting point (Tm), (iii) yield, and (iv) ferroelectric properties. For the first time, the molecular weight of nylon‐5 is characterized via size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, as well as matrix assisted laser desorption ionization time of flight mass spectroscopy (MALDI ToF‐MS), showing Mn values of up to 12 500 g mol‐1. Extended reaction times and the synthesis on a larger scale increase the molecular weight and yield. Nylon‐5 thin films are fabricated from a TFA:acetone (60:40 mol%) solvent mixture. Nylon‐5 thin‐film capacitors are ferroelectric and show a remanent polarization as high as 12.5 ± 0.5 μC cm‐2, which is stable in time. The high remanent polarization values, combined with the facile solution processing, render nylon‐5 a promising candidate for future microelectronic and multi‐ferroic applications.

Piezoelectric Nylon‐11 Fibers for Electronic Textiles, Energy Harvesting and Sensing

“…Nylons (or polyamides) fibers, introduced in the 1940s’ for the first time in stockings, are one of the most successful synthetic fibers with a well‐established textile industry. [ 10,11 ] Within the family, odd‐nylons constitute the natural choice for realization of e‐textiles if crystalized in their piezoelectric phase. For instance, nylon‐11, the well‐studied odd‐nylons, has various crystalline phases, namely α, α′ , ϒ , and δ′ of which only the δ′ ‐phase shows strong piezoelectric activity.…”

Polymer field-effect transistor memory based on a ferroelectric nylon gate insulator

“…A slight increase in the P r value is observed upon cycling, which is attributed to electric field induced polarization or electroforming. 28,29 It has been shown that nylon-11 films show fatigue-free performance that can even exceed that of PVDF and P(VDF-TrFE) capacitors. 28 We note that nylons are known for their water uptake.…”

Beyond nylon 6: polyamides via ring opening polymerization of designer lactam monomers for biomedical applications

“…Potassium t -butoxide catalyzes the polymerization of 2-pyrrolidone, 12,14,34 while 2-piperidone polymerization is catalyzed by tetramethyl-ammonium 2-oxopiperidin-1-ide 11 as well as alkali metals to produce nylon 4 and nylon 5, respectively. Other alkali metal and alkaline earth metal-based catalysts used for AROP of lactams include potassium pyrrolidonate, 28,35 and Grignard reagent.…”

“…Nylon 5 demonstrates superior ferro-electric property and thermal stability, however, ROP of 2-piperidone to prepare nylon 5 is challenging due to the low ring strain of the 6-membered cyclic-monomer as well as the low solubility of the resulting polymer (due to H-bonding and very high polarity). 11 Nylon 4 polymers are biodegradable 12,13 and show tenacity, elongation, elastic recovery, and moisture regain similar to cotton and other commercially available polyamide fibers. However, nylon 4 polymers are not commercially synthesized due to their low thermal stability, with melting point just above degradation temperature.…”