Conductive and Cytocompatible Poly(3,4)ethylene-dioxythiophene:poly(styrenesulfonate) Hierarchical Porous Materials: From Liquid to Solid Foams

Poly(3,4)ethylene-dioxythiophene (PEDOT), mainly associated with poly(styrenesulfonate) (PSS), is widely used to create thin conductive films or, more recently, conductive 3D porous materials as scaffolds for tissue engineering. Such conductive materials allow the direct delivery of electrical, electrochemical, and electromechanical stimuli to cells. Typically, surfactants are combined with the PEDOT:PSS dispersion to design conductive films by gelation. To the best of our knowledge, no foams have been reported using PEDOT:PSS/surfactant mixtures and a simple drying process. In this article, to develop a cytocompatible and conductive 3D porous material by a simple process, a PEDOT:PSS/cationic surfactant mixture was used to design solid foams by simple foaming followed by a drying step. We exploit the electrostatic interactions between negatively charged commercial PEDOT:PSS and positively charged N-octyltrimethylammonium bromide (C8TAB) surfactant to develop conductive solid foams via the solidification of liquid foams. The stable and homogeneous liquid PEDOT:PSS/C8TAB foams were dried to obtain solid and conductive foams with a high conductivity of 2.05 ± 0.80 S/cm. The high conductivity of the bulk PEDOT:PSS/C8TAB thin film, at 17 ± 4 S/cm, confirmed a doping effect of C8TAB. This increased conductivity in the presence of the surfactants is probably due to an increased interpenetration of the PEDOT:PSS particles during film formation. The resulting foams are highly conductive and noncytotoxic, allowing the proliferation of murine fibroblasts. These foams have great potential for biomedical applications.