A Highly Stable Ca2+ Ion-Selective Flexible Sensor Based on Treated PEDOT:PSS Transducing Layer

In this work, a highly conductive treated PEDOT:PSS (poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate)) layer was utilized for the transduction layer of an ion-selective flexible electrode (ISFE) and well-deposited on the carbon paste and polyethylene terephthalate (PET) substrate. The PEDOT:PSS was also treated by a co-solvent of ethylene glycol (EG) using bath-sonication to enhance electrical and electrochemical characteristics and finally coated with Ca2+ selective membrane cocktail. Electrochemical properties exhibited that EG treated PEDOT:PSS drop-casted ISFE achieves improved charge transport with remarkable electric conductivity enhancement. The fabricated Ca2+-ISFE was demonstrated a near-Nernst response of 31.9 mV/decade between 10-4 and 10-1 M with the rapid response (< 20 seconds). Moreover, the EG-treated PEDOT:PSS based ISFE proved significant potential stability with a negligible potential drift of 0.34 mV/min, compared to pristine PEDOT:PSS based ISFE (0.56 mV/min). Based on these analyses, it can be expected that the EG-treated PEDOT:PSS will pave the way for other bio-chemical compounds monitoring.