Beyond Doping and Charge Balancing: How Polymer Acid Templates Impact the Properties of Conducting Polymer Complexes

Polymer acids are increasingly used as dopants/counterions to access and stabilize the electrically conducting states of conducting polymers. Beyond doping and/or charge balancing, these polymer acids also serve as active components that impact the macroscopic properties of the conducting polymer complexes. Judicious selection of the polymer acid at the onset of synthesis or manipulation of the interactions between the polymer acid and the conducting polymer through processing significantly impacts the electrical conductivity, piezoresistivity, electrochromism, mechanical properties, and thermoelectric efficiency of conducting polymers. As polyelectrolytes, these polymer acids enable conducting polymer complexes to transport ions in addition to electrons/holes. Understanding the role of the polymer acid and its interactions with the conducting polymer generates processing-structure-function relationships for conducting polymer/polymer acid complexes, which can help overcome challenges that were associated with these materials, such as low electrical conductivity and sensitivity to humidity, and enable the design of conducting polymer complexes with desired functionalities.