Preparation of solid contact potentiometric sensors with self-plasticizing triblock polymer and ionic liquid-polymer composites

Triblock copolymer polystyrene-block-polybutadiene-block-polystyrene (PS-PB-PS, SBS) and its composites with ionic liquid have been applied for preparing solid contact ion-selective potentiometric sensors for the first time. Both types of materials form hydrophobic membranes with excellent mechanical properties. The proposed sensors containing ionophore and ion-exchanger exhibited the fast and Nernstian response to the primary ions and good selectivity over various interfering ions. The self-plasticizing property of triblock SBS enables the fabrication of completely solvent-free ion sensors. Such membranes showed much improved lifetime than the ones containing ionic liquid as plasticizer because the leaching of the ionic liquid has been eliminated. The SBS membrane is more hydrophobic than traditional plasticized poly vinyl chloride membrane, which prevents the formation of the water layer between the metal electrode substrate and the sensing membrane.