Semi-interpenetrating Polymer Networks Based on N-Isopropylacrylamide and 2-Acrylamido-2-methylpropane Sulfonic Acid for Hydrogel-based Chemical Sensors

Abstract

Stimulus-responsive hydrogels represent sensor elements with a high application potential for the detection of the concentration of a solved species. In combination with a piezoresistive pressure sensor, the hydrogel's analyte-dependent swelling pressure is transformed into an electrical output signal. In the past, numerous sensors with sensitivities to various analytes, like e.g. ethanol, glucose and pH, have been researched using this sensor principle [1]. However, the time span until a final steady-state value of the sensor's output signal is reached is typically in the range of minutes to hours due to the excessive diffusion processes associated with the gel's volume phase transition and visco-elastic behaviour.