Vacuum-assisted bilayer PEDOT:PSS/cellulose nanofiber composite film for self-standing, flexible, conductive electrodes

Sustainable cellulose nanofiber (CNF)-based composites as functional conductive materials have garnered considerable attention recently for their use in soft electronic devices. In this work, self-standing, highly flexible, and conductive PEDOT:PSS-CNF composite films were developed using a simple vacuum assisted filtration method. Two different composite films were successfully fabricated and then tested: 1) a single-layer composite composed of a mixture of PEDOT:PSS and CNF phases and 2) a bilayer composite composed of an upper PEDOT:PSS membrane layer and a CNF matrix sub-layer. The latter composite was constructed by electrostatic/hydrogen bonding interactions between PEDOT:PSS and CNFs coupled with sequential vacuum-assisted filtration. Our results demonstrated that the resultant bilayer composite film exhibited a competitive electrical conductivity (ca. 22.6 S cm(-1)) compared to those of previously reported cellulose -based composites. Furthermore, decreases in the electrical properties were not observed in the composite films when they were bent up to 100 times at an angle of 180 and bent multiple times at an angle of 90, clearly demonstrating their excellent mechanical flexibility. This study provides a straightforward method of fabricating highly flexible, lightweight, and conductive films, which have the potential to be used in high-performance soft electronic systems. (C) 2017 Elsevier Ltd. All rights reserved.