A sensor for measuring gel phase-transition temperature, with potential as a metal ion detector

This paper describes a sensor employing a get formed from an interpenetrating polymer network of poly(vinyl alcohol) and a copolymer of N-isopropylacrylamide and acrylic acid. This gel exhibits a continuous volume-phase transition that is strongly dependent on the presence of polyvalent metal ions in the gel solvent. A sensor apparatus has been constructed that estimates. in real time, the transition temperature of a gel. When this sensor is loaded with a gel sensitive to metal ions, it could be used to detect the presence and identity of metal ions in a solution.