title: Spin-coated polyethylene films probed by single molecules.
abstract: We have studied ultrathin spin-coated high-density polyethylene films by means of single-molecule spectroscopy and microscopy at 1.8 K. The films have been doped with 2.3,8.9-dibenzanthanthrene (DBATT) molecules, which function as local reporters of their immediate environment. The orientation distributions of single DBATT probe molecules in 100-200 nm thin films of high-density polyethylene differ markedly from those in low-density films. We have found a preferential orientation of dopant molecules along two well-defined, mutually perpendicular directions. These directions are preserved over at least a 2 mm distance. The strong orientation preference of the probe molecules requires the presence of abundant lateral crystal faces and is therefore not consistent with a spherulitic morphology. Instead, a "shish-kebab" crystal structure is invoked to explain our results.
authors.affiliation: Molecular Nano-Optics and Spins (MoNOS), Huygens Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands.
authors.forename: A C
authors.initials: AC
authors.lastname: Wirtz
authors.forename: C
authors.initials: C
authors.lastname: Hofmann
authors.forename: E J J
authors.initials: EJ
authors.lastname: Groenen