Fabrication of conducting polymer patterns for gas sensing by a dry technique

A dry fabrication technique to form conducting polymer patterns is presented. Such a technique can be particularly suitable for the implementation of conducting polymer arrays for gas sensing. The whole process, from sample preparation up to the polymerization process, is described. It basically consists of an in situ polymerization of the monomer in the vapour phase on a solid oxidizing salt formed on an insulating substrate under controlled conditions. Solid monomers were also polymerized using a purposely designed and realized reactor. The whole process was tested with a solid monomer belonging to the class of polyalkylthiophenes: homogeneous, repeatable conducting polymeric patterns were obtained and the results of their electrical and morphological characterization are reported and sensitivity to alcohol vapours tested. Various technological aspects of the process are discussed and a comparison with the more widely used wet polymerization techniques is reported.