Carboxylated poly(vinyl chloride)/plasticizer composite membranes as chemical sensor materials. Potentiometric response and water uptake properties

Carboxylated poly(vinyl chloride)/plasticizer composite membranes (without any ionophore or ligand) were prepared to determine their potentiometric response and water uptake properties. The composite membranes showed near-Nernstian or Nernstian response to alkali-metal cations, with a low selectivity. The potentiometric response was relatively stable and reproducible as compared with unmodified poly(vinyl chloride)-based membranes. The carboxylated poly(vinyl chloride) membranes showed high water content in aqueous media in spite of the hydrophobic nature of the plasticizers. The water uptake properties of the membranes are discussed in connection with their utilization as chemical sensor materials.