title: Simulation study of field-induced morphological changes in a proton-conducting ionomer.
abstract: A simulation study was made of the effects of strong electric fields on the morphology of a Nafion-like ionomer at various levels of hydration. The results of united-atom molecular-dynamics computations showed a self-organization of the side chain terminal groups into cylindrical clusters. The walls of these clusters contain the sulfonate dipoles, while the interior holds the majority of the water molecules. These cylindrical structures then align to form an hexatic array aligned along the direction of the applied electric field. The hexatic morphology persists after the removal of the field. A calculation by means of the Kirkwood coupling parameter method shows the Helmholtz free energy of the hexatic morphology of the poled membrane to be lower than that of the initial isotropic material, even in the absence of the applied field.
authors.affiliation: Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Elshad
authors.initials: E
authors.lastname: Allahyarov
authors.forename: Philip L
authors.initials: PL
authors.lastname: Taylor
authors.forename: Hartmut
authors.initials: H
authors.lastname: Löwen
mesh_terms: D003198:Computer Simulation; D004553:Electric Conductivity; D004574:Electromagnetic Fields; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry* / Q000528:radiation effects*; D011522:Protons
chemical_list: D011108:Polymers; D011522:Protons