Photocurable Polymer Matrixes for Potassium-Sensitive Ion-Selective Electrode Membranes

Photocurable oligomers based on urethane and Bisphenol A (epoxy) diacrylates have been studied as an alternative polymer matrix for ion-selective membranes of ion sensors. The compatibility of the polymers with various plasticizers commonly used in PVC-based ion-selective membrane formulations has been tested, and it has been shown that the urethane-based membranes may hold more than 50% of a plasticizer, while epoxy-based compositions are not fully compatible with them. Potassium sensitive electrodes with an inner reference solution and a membrane formed by photocured urethane containing valinomycin as the ionophore have been investigated. The influence of the amount and the type of photoinitiator, cross-linking agent, and plasticizer on ion response of the ion-selective electrode has been studied. Ion-selective electrodes with an optimized membrane composition show a sensitivity of 57 mV/decade, a range of linear response from 1 to 10-5 mol/L of KC1, and a limit of detection around 10-6 mol/L. The developed polymer matrix was used to make an ISFET-based potassium sensor. © 1995, American Chemical Society. All rights reserved.