We have determined the orientations of poly[ 4,4′-oxydiphenylene-pyromellitimide] (PMDA-ODA) molecules in rubbed and unrubbed polyimide films ( ∼120 Å) on Si substrates by polarized IR absorption spectroscopy. We found that for rubbed films the polymer chains are oriented along the rubbing direction and are tilted up on average by 8.5° from the surface plane. We conclude that the polymer chain inclination induced by rubbing determines the tilt of the director of the bulk liquid crystal.
No takes yet. Share an insight, caveat, or question.
Sakamoto et al. (1994) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: