An extended site-binding model and experimental results of organic membranes for reference ISFETs

Abstract An extended site-binding model for hydrophobic and blocked organic polymers is proposed. The model is based on the assumption that two kinds of surface sites exist (COOH and COH groups). These groups can be formed in the presence of oxygen and water in the electrolyte. The pH response of various hydrophobic organic polymer membranes is measured. Calculated and experimentally measured surface potentials show good agreement in the whole pH region from 1 to 12. The influence of surface passivation and annealing on the long-term response is also investigated.