Direct printing of conductive polymer PEDOT:PSS for foldable transient electronics

Abstract

With the increased demand on portability, electronics have progressed from rudimentary flexible electronics to foldable electronics. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), a conductive polymer, is a promising material for achieving foldable electronics, due to its mechanical stability. In foldable electronics, however, inadequate physical adhesion between electrodes and substrates under folding deformation has been a challenge. It can cause interfacial delamination and electronic failure during the folding and unfolding processes. In this study, electrohydrodynamic (EHD) printing is utilized for the fast, low-cost, and high-resolution fabrication of PEDOT:PSS circuits onto polyvinyl alcohol (PVA) films to improve the interface binding force for foldable electronics. The morphology and electrical properties of PEDOT:PSS patterns with different printed conditions were experimentally investigated. The adhesion between the printed PEDOT:PSS circuits and the PVA film was characterized by tape adhesion test, and the electrical property remained almost unchanged after 50 peeling tests. We demonstrated excellent foldability of the printed electronics. After 4 folds (16 layers), the resistance of PEDOT:PSS circuits varied minimally, and the external LED lights remained operational while folding and unfolding. Moreover, using the water soluble and degradable PVA substrate, the printed circuits can be simply dissolved in water, which provide a promising approach toward transient electronics and green electronics, and reduce the electronic waste.