Breakthrough in chemical analysis of Intrinsically Conducting Polymers (ICPs) enables easier identification of polymers suitable for different prospective applications. Researchers at IIT Bombay have come up with a novel and much simpler method to quantify their charge storage characteristics.

Ever wondered what connects power equipments, batteries, microelectronics, electromagnetic interference shields and micromachines? It is a new technological marvel called Intrinsically conducting polymers. These polymers with a high electrical conductivity have stirred intense interest in the research and development community lately. Conducting polymers are used in applications ranging from electrodes for batteries and sensors to antistatic space suits. The colour of the polymer film changes with a change in the electric potential so that such materials could be used to glaze windows to cut out the glare of sunlight; by turning blue at a higher potential. The same property of these polymers lends to them their potential for application in electrochromic displays.

Ms. Asfiya Q. Contractor and Prof. Vinay A. Juvekar of Department of Chemical Engineering  have developed a novel method to quantify the charge storage characteristics of different conducting polymers. The work aids in a fundamental understanding of the charging-discharging behaviour of conducting polymers. Compared to Electron Spin Resonance and Raman spectroscopy, which are the currently available techniques to investigate the charge storage characteristics of the ICPs, the new, and much simpler, redox reaction based technique not only gives a more accurate quantification of the characteristics, but also enables us to find out the energies of charge carriers in each charging regime. The research paper has recently been published in the journal of Analytical Chemistry of the American Chemical Society, which is one of the most prestigious journals on the subject.

The simplicity of the experiment, would also help in simplifying the analysis of the results. ”When the experiment is complicated, the analysis of results also gets complicated”, the author explains. The method developed is general and can be applied to investigate charge storage characteristics of other intrinsically conducting polymers as well,  thereby providing an useful tool to choose and tune ICPs for various applications.

The method is expected to exhibit a potential impact in the future. Conducting polyaniline films, used in the work, could prove advantageous over the conventional capacitors and carbon electrodes. Conducting polymers exhibit a property called ‘pseudocapacitance’; where they store charge in the bulk of the material  compared to conventional carbon electrodes that store only on the surface.  Moreover, the fabrication of these films can be  easily done in a dilute acid medium at room temperature, thus eliminating special fabrication requirements.