Electrogelation of PEDOT:PSS and its copolymer for bioelectronics

This paper explores the combination of screen-printing and electrogelation of PEDOT:PSS, including non-solution-processable PEDOT:PSS-copolymers, to fabricate scalable and cost-effective coated devices for bioelectronic applications. There is strong interest in developing scalable deposition techniques for conducting polymer coatings for applications in bioelectronics. Here, we explore the potential of electrogelation to develop coatings from poly(3,4-ethylenedioxythiophene) polystyrene sulphonate (PEDOT:PSS) and its copolymer with poly (styrene sulphonate- co -styrene methanamine) (PEDOT:PSS- co -PSMA). The coatings were used to lower the impedance of screen-printed silver electrodes, leading to a decrease in the voltage needed to achieve cutaneous stimulation of small fibres and an increase in the signal-to-noise ratio in cutaneous biopotential recordings. Additionally, PEDOT:PSS- co -PSMA was integrated as the gate electrode in an organic electrochemical transistor, showing improved performance compared to non-modified and PEDOT:PSS-coated gold electrodes, i.e. , a threshold voltage decreased from 0.7 V for pristine gold to 0.5 V for the PEDOT:PSS- co -PSMA gate electrode. The results show that electrogelation offers a scalable and cost-effective solution for the deposition of conducting polymers, including non-solution-processable conducting polymers, as performance-enhancing coatings for bioelectronic applications.