Preparation of conductive polymer foams and their application as chemical sensors

摘要

Intrinsically conducting polymers (ICPs) possess advantageous features for sensor applications. A diverse range of polymers is available via the electrochemical or chemical polymerization of various monomer types. The sensitivity of an ICP-based sensor can be readily varied by changing the polymerization conditions and the counterion used as the dopant. The conductivity of ICPs is stable for long times and their thermal stability is quite good compared with other organic polymers. For an ICP-based sensor application, the signal can be measured as a change in resistance or conductivity, and reversible responses are typically obtained in relatively short time periods at ambient temperatures. Biomaterials such as enzymes, antibodies, and cells may be incorporated into the ICP structure to create specific biosensors. There are numerous examples of ICPs used as volatile organic compound (VOC) sensors. However, obtaining chemical diversity in ICPs involves significant synthetic effort, such as modification of the polymer backbone or modification of substituent groups. An alternative approach to varying the ICP structure is to use composites formed from a conducting material dispersed into a variety of insulating polymeric phases. A wide variety of insulating polymers can be used as components of these types of detector elements, resulting in a chemically diverse set of resistive detectors having good vapor classification properties. However, very few sensors developed from conducting polymers within a porous substrate have been reported.