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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 5: Composites and Functional Polymer Hybrids
CPP 5.4: Talk
Monday, March 17, 2025, 12:30–12:45, H38
Water dynamics in conductive PEDOT:PSS/cellulose nanocomposite films in dependence of relative humidity — •Lucas P. Kreuzer1, Marie Betker2, Marcell Wolf1, Daniel Söderberg3, and Stephan Roth2,3 — 1Heinz Maier-Leibnitz-Zentrum, Technische Universität München — 2Deutsches Elektronen Synchrotron DESY — 3Department of Fibre and Polymer Technlogy, KTH Royal Institute of Technology
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a conductive polymer blend widely used in organic electronics. However, pure PEDOT:PSS films absorb significant amounts of water (≈50 V%), causing swelling, degradation, and eventually a decrease in conductivity. Integrating PEDOT:PSS with cellulose nanofibrils (CNFs) overcomes these issues by limiting water absorption and enhancing mechanical stability. However, in humid environments, a minor amount of water is still absorbed, leading to a change in film morphology: the absorbed water induces de-wetting of PEDOT:PSS from the CNFs, reducing conductivity, whereas drying generally leads to a re-wetting of PEDOT:PSS, thereby restoring conductivity. To investigate further the role of water, quasi-elastic neutron scattering is applied, which reveals two water species in the films: mobile bulk water and slower hydration water. Upon drying, bulk water is released completely, while hydration water remains in the films, supporting the re-wetting of PEDOT:PSS. QENS also provides information on the diffusive and hydrogen-bonding behavior of water.
Keywords: cellulose; PEDOT:PSS; conductive; organic electronics; neutron scattering