Process for preparing electro-conductive polymer films by doping neutral polymers

摘要

Process for preparing films of electroconductive polymers by treatment of neutral polymers with doping agents and sensors of chemical substances obtained with such films. The sensors can be in particular conducting pi -conjugated polymer chemi-resistors made chemically and having high sensitivity to vapours of organic substances. The sensors consist of a film of conducting polymer that can be laid with known techniques onto insulating supports starting from a stable suspension in organic solvents. The suspension is obtained by neutral preformed pi -conjugated polymers dissolved in organic solvents with addition of small and suitable amount of dopant diluted in organic solutions. The conducting film that is obtained directly for evaporation of the solvents from the suspension deposited onto the supports, is mechanically compact, strong, stable and adhesive with electrical conductivity of about 10<-3>-10<-5> S/cm. The sensors are reproducible in electrical resistance and in type of response versus variation of resistance ratio DELTA R/R% and the response is reversible in a few seconds. The method of production of the sensors is simple, quick and not expensive and is suitable for industrial application; also the system for detecting the signal is simple and not expensive being an electrical resistance measure. <IMAGE>