ATOMIC-FORCE MICROSCOPY OF MECHANICALLY RUBBED AND OPTICALLY BUFFED POLYIMIDE FILMS

Polymer coated substrates modified both by mechanical rubbing and opti cal buffing have been found to cause liquid crystal molecules to align . Atomic force microscopy (AFM) was used to characterize the differenc es and similarities in polyimide substrate coatings after being subjec ted to these two processes. Though the buffing processes caused simila r alignment on the surfaces, it was found that the mechanical rubbing created grooves on the order of 250 nm, whereas optical buffing result ed in no changes to topographic structure on the order of 100 nm scale and some variations at smaller scales. From this observation it was c onfirmed that the interaction causing the alignment must be associated with molecular alignment rather than large scale physical grooving.