title: Structure of zone-cast HBC-C12H25 films.
abstract: The structure of a thin zone-cast film of the hexa-n-dodecyl-substituted hexa-peri-benzocoronene (HBC) has been investigated using grazing incidence X-ray diffraction. A model with an orthorhombic unit cell containing two molecules accounts well for the observations. The molecules are arranged in a "herringbone" structure resembling the packing observed for unsubstituted HBC. The molecular disk planes are oriented perpendicularly to the substrate, rotated by approximately 39 degrees about the film normal. The relatively long side chains of dodecyl were found to be in an ordered interdigitated state. The aliphatic side chains and the aromatic HBC-cores segregate to form regular vertical domains spanning the film thickness. For in-plane rocking scans a discrete orientation distribution is observed with peaks at regular angle intervals. We interpret this as a grain boundary effect induced by alkyl chain stacking faults.
authors.affiliation: Danish Polymer Centre, Risø National Laboratory, P.O. Box 49, 4000 Roskilde, Denmark. dag.werner.breiby@risoe.dk
authors.forename: Dag W
authors.initials: DW
authors.lastname: Breiby
authors.forename: Oliver
authors.initials: O
authors.lastname: Bunk
authors.forename: Wojciech
authors.initials: W
authors.lastname: Pisula
authors.forename: Theis I
authors.initials: TI
authors.lastname: Sølling
authors.forename: Adam
authors.initials: A
authors.lastname: Tracz
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Pakula
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Martin M
authors.initials: MM
authors.lastname: Nielsen