Electrically conducting polymers: Materials of the twentyfirst century

The paper critically reviews some recent developments in the field of electrically conducting polymers which have grown very rapidly since the discovery that there is a very sharp increase in conductivity when intrinsically insulating organic conjugated polymers such as, polyacetylene are doped with oxidizing or reducing agents. These polymers, also called synthetic metals, combine the electrical properties of polymers with the advantages of polymers and have such a vast scope of diverse applications that these are being perceived as the materials of the twentyfirst century. Doped organic conducting polymers, though conducting, suffer from two disadvantages of chemical instability and poor processibility. One of the fundamental challenges in the field of conducting polymers, therefore, is to design low band gap intrinsically conducting polymers so that there is no need to dope them. Various strategies presently used for designing polymers with tailor-made conduction properties and some recent results obtained using these strategies are discussed. Lastly, some of the important applications of electrically conducting polymers are also discussed with a view to highlight the great potential of these materials.