Redox active polymer devices and methods of using and manufacturing the same

A tag apparatus, comprising:

• a substrate;
• a conductive structure formed on the substrate and comprising a layer of redox-active polymer having mobile ions and mobile electrons, the conductive structure further comprising a first terminal and a second terminal configured to receive an electrical signal therebetween,
• wherein the layer of redox-active polymer is configured to conduct an electrical current generated by the mobile ions and the mobile electrons in response to the electrical signal;
• and
• a detection circuit operatively coupled to the conductive structure and configured to detect the electrical current flowing through the conductive structure,
• wherein the layer of redox-active polymer comprises a zwitterionic polymer unit configured to reversibly switch between a zwitterionic state in which the zwitterionic polymer unit has first and second charge centers having opposite charge states that compensate each other, and a non-zwitterionic state in which the zwitterionic polymer unit has one of the first and second charge centers whose charge state is compensated by mobile counterions that migrate in and out of the zwitterionic polymer unit.