Conducting polymers in sensor applications
Conducting (or conjugated) polymers (CPs) are widely used for fabricating chemical and biosensors. These materials enable fabrication of devices in short lead time and at relatively low costs owing to their unique advantages of light weight, easy processability, compatibility with biological systems, tunable electronic and optic properties, large area fabrication and potential for flexible or wearable sensors. This chapter describes the basic concepts underlying the interaction of analyte with CPs as well as the other components of sensors. The operating principles of transducers used in the sensor are discussed in detail. Sensors based on conducting polymers are classified in accordance with the changes in the properties of conducting polymers. These changes involve changes in (i) doping levels, (ii) optical properties and (iii) changes due to weak interactions. Furthermore, the sensors have been reviewed for various conducting polymers such as polyaniline, polythiophene, polypyrrole, polydaicetylene for analysis of wide variety of analysts including toxic gases, radiation, pH, temperature, external stimuli; and recent advances in sensors based on conducting polymers have been discussed. Future directions and thrust in emerging field have been projected in the area of molecular engineering, material synthesis, film preparation and transducers, circuits and algorithms for developing futuristic sensors especially wearable sensors.