Regular,adjacent reentry folding in single crystals of a liquid crystal polymer crystallized from the nematic state

Folded chain single crystals 35 Å thick have been grown from the liquid crystal state of an aromatic-aliphatic azomethine ether polymer (AZMEP-n) having a 10-carbon flexible segment (n = 10). Electron diffraction has permitted refinement of the triclinic unit cell. The molecular axes lie at an ca. 65° angle to the lamella normal and fold every third chemical repeat distance. For AZMEP-1 and -8 extended chain lamellae are formed; for AZMEP-7 both folded and extended chain lamellae are found. The observations of folded chain lamallae are in agreement with prior suggestions from our laboratory of chain folding in the liquid crystalline state in thin films. © 1992 John Wiley & Sons, Inc.