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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: Interfaces and Thin Films I

CPP 20.2: Vortrag

Dienstag, 18. März 2025, 12:00–12:15, H38

Highly Electrically Conductive PEDOT:PSS films via Layer-by-Layer Electrostatic Self-Assembly — •Muhammad Khurram, Sven Neuber, Annekatrin Sill, and Christiane A. Helm — muhammad.khurram@uni-greifswald.de

Electrically conductive films of Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) (PEDOT:PSS) are usually formed by spin coating of aqueous dispersions with PEDOT:PSS nanoparticles. The adsorption conditions are investigated using dip coating and a flow cell with different flow rates. Multilayer films are formed by sequential adsorption of oppositely charged macromolecules. PEDOT:PSS serves as polyanion, and PDADMA is the polycation. In dip coating, the first layer consists of approximately 70 nm thick monolayer of PEDOT:PSS nanoparticles. Subsequent PDADMA/PEDOT:PSS bilayers have a low, constant thickness (9.5 nm). Using the flow cell (0.2 mL/min) for film preparation also resulted in a constant PDADMA/PEDOT:PSS bilayer thickness (7.5 nm). PEDOT:PSS nanoparticle monolayers could also be observed with the flow cell, but only if the washing step after PEDOT:PSS adsorption was omitted. The films prepared by flow cell showed the highest conductivity (230 kS/m) and the lowest roughness (2 - 4 nm). We propose that the adsorption in a flow cell leads to a nearly flat orientation of the PEDOT molecules, increasing charge carriers’ mobility. We also find that the relative humidity strongly influences the volume density and mobility of the charge carriers

Keywords: PEDOT:PSS; Conductive coating; Polyelectrolyte multilayer; Layer-by-Layer coating; Flow cell coating