Filters

20202

More filters

20222
Reset filters

Settings

Type: article × Publisher: Chichester [u.a.] : Wiley × Subject: Konferenzschrift ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Heterogeneous freezing on pyroelectric poly(vinylidene fluoride-co-trifluoroethylene) thin films
    (Chichester [u.a.] : Wiley, 2020) Apelt, Sabine; Höhne, Susanne; Uhlmann, Petra; Bergmann, Ute
    Active deicing of technical surfaces, such as for wind turbines and heat exchangers, currently requires the usage of heat or chemicals. Passive coating strategies that postpone the freezing of covering water would be beneficial in order to save costs and energy. One hypothesis is that pyroelectric active materials can achieve this because of the surface charges generated on these materials when they are subject to a temperature change. High-quality poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) thin films with a high crystallinity, prefererd edge-on orientation, low surface roughness, and comprised of the β-analogous ferroelectric phase were deposited by spin-coating. Freezing experiments with a cooling rate of 1 K min−1 were made on P(VDF-TrFE) coatings in order to separate the effect of different parameters such as the poling direction, film thickness, used solvent, deposition process, underlying substrate, and annealing temperature on the achievable supercooling. The topography and the underlying substrate significantly changed the distribution of freezing temperatures of water droplets in contact with these thin films. In contrast, no significant effect of the thickness, morphology, or pyroelectric effect of the as-prepared domain-state on the freezing temperatures was found.
  • Thumbnail Image
    Item
    Charge transfer characteristics of F6TCNNQ–gold interface
    (Chichester [u.a.] : Wiley, 2020) Kuhrt, Robert; Hantusch, Martin; Knupfer, Martin; Büchner, Bernd
    The metal–organic interface between polycrystalline gold and hexafluorotetracyanonaphthoquinodimethane (F6TCNNQ) was investigated by photoelectron spectroscopy with the focus on the charge transfer characteristics from the metal to the molecule. The valence levels, as well as the core levels of the heterojunction, indicate a full electron transfer and a change in the chemical environment. The changes are observed in the first F6TCNNQ layers, whereas for further film growth, only neutral F6TCNNQ molecules could be detected. New occupied states below the Fermi level were observed in the valence levels, indicating a lowest unoccupied molecular orbital (LUMO) occupation due to the charge transfer. A fitting of the spectra reveals the presence of a neutral and a charged F6TCNNQ molecules, but no further species were present.