Abstract: A gas sensor for use in monitoring gases such as H2S, NO2 or SO2 comprises a film or layer of non-protonated polyaniline as the gas sensing material.

Abstract: Device adapted for efficient light emission including a plurality of component layers of which a first outer layer is adapted for electron injection, a second opposing outer layer is adapted for hole injection, and plural intermediate layers arranged therebetween for charge semi-conduction. The intermediate layers include at least one semi-conducting polymer adapted for hole transport and/or electron blocking, and at least one semi-conducting polymer adapted for hole blocking and/or election transport. The at least one semi-conducting polymer adapted for electron transport and/or hole blocking comprises polymer selected from a nitrogen and/or sulphur containing polymer which is partially or substantially conjugated.

Abstract: A polyaniline is characterized by a nuclear magnetic resonance spectrum in its leuco form showing only two .sup.13 C peaks, indicating the substantal absence of chain branching, and preferably by a molecular weight (M.sub.p) above 90,000 and up to about 170,000 (more especially 100-140,000). Oriented films of such polyanilines in the protonated emeraldine oxidation state have electrical conductivities up to at least around 500 S/cm.They may be made by oxidizing aniline in aqueous solution with a persulfate under the combination of conditionsthat the acidity of the solution throughout the reaction is such that if its temperature is adjusted to 20.degree. C. it will have a pH in the range from about -0.2 to +3.0;that the temperature of the solution is in the range from -5.degree. to about -40.degree. C.