Temperature triggered ion-selective membranes for non-zero current electrochemical ion sensors

Abstract

• A temperature triggered ion-selective membrane intended for non-zero current ion sensing is presented. • The liquid type membrane offers well developed electrochemical signals for changes of analyte ions concentration both in voltammetric and coulometric mode. • The solidified membrane is characterized by low electrochemical activity and offers easy storage. • The proposed system may be regarded as an electrochemical thermometer. A temperature triggered ion-selective membrane intended for non-zero current ion sensing is presented for the first time. At temperatures lower than 17 °C the membrane is in a solidified state, whereas above this temperature spontaneous transformation to a liquid state is observed. In the liquid state the diffusion coefficient of the analyte ions is higher than for a typical polymeric ion-selective membrane, resulting in higher current. Thus, the liquid type membrane offers well developed electrochemical signals for changes of analyte ions concentration both in voltammetric and coulometric mode, whereas the solidified type membrane is characterized by low electrochemical activity. Therefore, the herein proposed system may be regarded also as an electrochemical thermometer and it offers easy handling or storage while in the solidified form at low temperature, and benefits from liquid phase electrochemistry at room temperature.