title: Structure of langmuir-blodgett films of disk-shaped molecules determined by atomic force microscopy.
abstract: Monolayer Langmuir-Blodgett films of a discotic mesogen have been studied with atomic force microscopy (AFM). These measurements confirm the "edge on" arrangement for the disk-shaped molecules suggested by surface pressure-area isotherms and show that the molecules form columns that are separated by 17.7 angstroms +/- 10 percent. Column alignment is found to be predominantly along the film deposition direction, with an angular spread of 35 degrees . The AFM images also show that the mean disk separation within the columns is 5.1 +/- 1.3 angstroms, in good agreement with x-ray diffraction (XRD) results. Roomtemperature XRD measurements on bulk samples of the same material indicate a disordered-hexagonal liquid crystalline mesophase, with a column-to-column spacing of 19.9 +/- 0.2 angstroms.
authors.forename: J Y
authors.initials: JY
authors.lastname: Josefowicz
authors.forename: N C
authors.initials: NC
authors.lastname: Maliszewskyj
authors.forename: S H
authors.initials: SH
authors.lastname: Idziak
authors.forename: P A
authors.initials: PA
authors.lastname: Heiney
authors.forename: J P
authors.initials: JP
authors.lastname: McCauley
authors.forename: A B
authors.initials: AB
authors.lastname: Smith