Contact
    Start Publications Crystallization of Poly(ethylene)s with Regular Phosphoester ...
    ←  Publication Finder
    KSV NIMA

    Crystallization of Poly(ethylene)s with Regular Phosphoester Defects Studied at the Air-Water Interface

    Year: 2020

    Journal: Polymers, Volume 12, OCT

    Authors: Hasan, Nazmul; Busse, Karsten; Haider, Tobias; Wurm, Frederik R.; Kressler, Joerg

    Organizations: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)German Research Foundation (DFG) [189853844 TRR 102]

    Keywords: poly(ethylene); Langmuir-Blodgett film; crystallization; AFM and GI-WAXS

    Poly(ethylene) (PE) is a commonly used semi-crystalline polymer which, due to the lack of polar groups in the repeating unit, is not able to form Langmuir or Langmuir-Blodgett (LB) films. This problem can be solved using PEs with hydrophilic groups arranged at regular distances within the polymer backbone. With acyclic diene metathesis (ADMET) polymerization, a tool for precise addition of polar groups after a certain interval of methylene sequence is available. In this study, we demonstrate the formation of Langmuir/LB films from two different PEs with regular phosphoester groups, acting as crystallization defects in the main chain. After spreading the polymers from chloroform solution on the water surface of a Langmuir trough and solvent evaporation, the surface pressure is recorded during compression under isothermal condition. These pi-A isotherms, surface pressure pi vs. mean area per repeat unit A, show a plateau zone at surface pressures of similar to (6 to 8) mN/m, attributed to the formation of crystalline domains of the PEs as confirmed by Brewster angle and epifluorescence microscopy. PE with ethoxy phosphoester defects (Ethoxy-PPE) forms circular shape domains, whereas Methyl-PPE-co-decadiene with methyl phosphoester defects and two different methylene sequences between the defects exhibits a film-like morphology. The domains/films are examined by atomic force microscopy after transferring them to a solid support. The thickness of the domains/films is found in the range from similar to (2.4 to 3.2) nm depending on the transfer pressure. A necessity of chain tilt in the crystalline domains is also confirmed. Grazing incidence X-ray scattering measurements in LB films show a single Bragg reflection at a scattering vector q(xy) position of similar to 15.1 nm(-1) known from crystalline PE samples.
    View publication