Flexible and conductive multilayer films based on the assembly of PEDOT:PSS and water soluble polythiophenes

Flexible conductive polyelectrolyte multilayer films built upon anionic poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and cationic poly(3-hexylthiophene)-based conjugated polyelectrolytes (P3HT-R) containing imidazolium, pyridinium and phosphonium ionic groups were prepared using electrostatic layer-by-layer assembly. Adsorbed amount of each polyelectrolyte strongly increases when divalent cations (Ba2+) are employed as electrolyte and when the rinsing step is avoided during the build-up. The electrical properties of these (P3HT-R/PEDOT:PSS)n multilayer films were then investigated using the van der Pauw method leading to an average conductivity of ∼2 S m−1. Semiconducting behavior of these organic coatings was demonstrated by the direct relationship between the conductivity and the temperature. (P3HT-R/PEDOT:PSS)n multilayer films exhibited p-type semiconducting behavior as showed by Seebeck measurements. Finally, these films were successfully deposited onto flexible polymer sheets and their conductivity was found to be not affected by applying a bending stress. [Display omitted] •Layer-by-layer assembly of π-conjugated cationic polyelectrolytes bearing different side groups and PEDOT:PSS.•Polyelectrolyte multilayer adsorption followed in-situ by optical reflectometry.•Preparation of p-type organic semiconductors onto rigid and flexible substrates.•Electrical conductivity was not affected when a bending stress is applied.