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This communication reports on a versatile and substrate‐agnostic method to tune the surface chemistry of conducting polymers with the aim of bridging the chemical mismatch between bioelectronic devices and biological systems. As a proof of concept, the surface of poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is grafted with a short‐chain oligoethylene glycol monolayer to favor the formation of cell‐derived supported lipid bilayers (SLBs). This method is tuned to optimize the affinity between the supported lipid bilayer and the conducting polymer, leading to significant improvements in bilayer quality and therefore electronic readouts. To validate the impact of surface functionalization on the system's ability to transduce biological phenomena into quantifiable electronic signals, the activity of a virus commonly used as a surrogate for SARS‐CoV‐2 (mouse hepatitis virus) is monitored with and without surface treatment. The functionalized devices exhibit significant improvements in electronic output, stemming from the improved SLB quality, therefore strengthening the case for the use of such an approach in membrane‐on‐a‐chip systems. [ABSTRACT FROM AUTHOR]

In organic mixed ionic–electronic conductors (OMIECs), it is critical to understand the motion of ions in the electrolyte and OMIEC. Generally, the focus is on the movement of net charge during gating, and the motion of neutral anion–cation pairs is seldom considered. Uptake of mobile ion pairs by the semiconductor before electrochemical gating (passive uptake) can be advantageous as this can improve device speed, and both ions can participate in charge compensation during gating. Here, such passive ion pair uptake in high‐speed solid‐state devices is demonstrated using an ion gel electrolyte. This is compared to a polymerized ionic liquid (PIL) electrolyte to understand how ion pair uptake affects device characteristics. Using X‐ray photoelectron spectroscopy, the passive uptake of ion pairs from the ion gel into the OMIEC is detected, whereas no uptake is observed with a PIL electrolyte. This is corroborated by X‐ray scattering, which reveals morphological changes to the OMIEC from the uptake of ion pairs. With in situ Raman, a reorganization of both anions and cations is then observed during gating. Finally, the speed and retention of OMIEC‐based neuromorphic devices are tuned by controlling the freedom of charge motion in the electrolyte. [ABSTRACT FROM AUTHOR]

Electrochemically induced volume changes in organic mixed ionic‐electronic conductors (OMIECs) are particularly important for their use in dynamic microfiltration systems, biomedical machinery, and electronic devices. Although significant advances have been made to maximize the dimensional changes that can be accomplished by OMIECs, there is currently limited understanding of how changes in their molecular structures impact their underpinning fundamental processes and their performance in electronic devices. Herein, a series of ethylene glycol functionalized conjugated polymers is synthesized, and their electromechanical properties are evaluated through a combined approach of experimental measurements and molecular dynamics simulations. As demonstrated, alterations in the molecular structure of OMIECs impact numerous processes occurring during their electrochemical swelling, with sidechain length shortening decreasing the number of incorporated water molecules, reducing the generated void volumes and promoting the OMIECs to undergo different phase transitions. Ultimately, the impact of these combined molecular processes is assessed in organic electrochemical transistors, revealing that careful balancing of these phenomena is required to maximize device performance. [ABSTRACT FROM AUTHOR]