Na+ ion selectivity study of a crown ether functionalized PEDOT analog

An electropolymerized ion selective PEDOT analog is presented in this communication. Poly-(2-phenyl-15crown-5-(3,4-ethylene-dioxythiophene)-amine) (PEDOT-Crown15) showed excellent electrochemical stability with a fast electron transfer (ΔEp = 50 mV). In comparison with unmodified PEDOT, a faster change from isolating to conducting state was observed. This is attributed to the formation of a well-ordered internal polymer matrix, caused by the aniline-Crown15 moiety. In-situ electrochemical conductance measurements in the presence of different monovalent cations showed high affinity for Na+ ions, as evidenced by the decrease of the conductance of the polymer in comparison with K+ and Li+. This selectivity is attributed to a limitation of the charge hopping conductance.