SCANNING TUNNELING MICROSCOPY IMAGES OF POLY(ETHYLENE OXIDE) POLYMERS - EVIDENCE FOR HELICAL AND SUPERHELICAL STRUCTURES

Scanning tunneling microscopy images of single, double, and multistranded helical structures of bulk poly(ethylene oxide) polymers (PEO) are presented. The single-stranded helix appears to contain seven PEO monomer units with two turns per repeat unit consistent with the model proposed by Tadokoro; individual monomer units are visible. The multistranded STM images are similar to those obtained by transmission electron microscopy, but smaller in scale. A hierarchy of superhelical structures is proposed to account for the observed images.