ELECTRON MICROSCOPY OF POLY(O-ACETYL HYDROXY-L-PROLINE) CRYSTALS

Single crystals of POAHP II were grown from acetic anhydride, a solvent in which POAHP I is thought to be stable. The single crystals gave an electron diffraction pattern which specified a hexagonal unit cell and the lateral spacing between molecular chains (11.4 Å). There is reasonable indication that molecular chain folding occurs in the POAHP single crystals. Epitaxial crystallization of POAHP II has been observed in the [100] and [320] directions on NaCl, [110] direction on KCl, and [100] direction on KI. Evidence indicates that the molecular axis is normal to the long axis of the POAHP needles and parallel to the substrate surface. Copyright © 1969 John Wiley & Sons, Inc.