Original Crystal Structures of Even–Even Polyamides Made of Pleated and Rippled Sheets

Original crystal structures of even–even polyamides are introduced. They based on twisted conformations at the amide-aliphatic part links and reminiscent pleated rippled protein sheet introduced by Pauling Corey in early 1950s. Pleated sheets chiral, made two conformational isomers. have specific X-ray diffraction “profiles”. Publications describe such profiles, indicating that both variants exist. The structure is stable form whole family nylons 2,2n. applies for a high-temperature “alpha phase variant” with long aliphatic parts more generally appears to be (one of?) so-called “high-temperature ? phase(s)” nylons. appear entropically favored, form(s) This new their possible different sequences junctions open way (re)analysis rare unusual morphologies produced high Tc after partial melting/self-seeding.