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A new type of realisation of the hydrotalcite‐type lamellar compound Zn2AI(OH)6Cl.nH2O is described, using an original ink composed of a concentrated aqueous suspension of Zn2AI(OH)6Cl.nH2O powder, which, when applied by the screen‐printing technique, in particular environmental conditions—in a high relative humidity atmosphere—permits one to obtain very satisfactory deposits. Optical characterisation shows good resolution and levelling of the screen‐printed layer. X‐ray patterns show a high orientation of the (hkO) reticular planes of the screen‐printed material in a direction parallel to the substrate; this is a very interesting characteristic related to experiment on the electrical properties of this type of compound. Tests show the good adherence of the deposited layer on alumina or glass. Future applications are envisaged.

The electrical properties related to the hydration of the hydrotalcite‐type lamellar compound Zn2Al(OH)6Cl.nH2O are such as to permit the realisation of a humidity sensor. The sensor is achieved by depositing thick film by the screen‐printing technique. First, the means of forming the material is optimised. Two types of sensor are then realised, one working with direct current, the other with alternating current. The performance of each device is studied by means of specified experiments. The authors create a new measurement cell for calibrating the alternating current sensor. Response time measurements are carried out, and results are interpreted and compared.

The present and potential applications of screen‐printing thick film technology to the field of chemical sensing are briefly reviewed in the first part of the paper. The second part is devoted to the search for new routes to selectivity for basically non‐selective gas sensors.