Benefits of increasing surface to volume ratio for improving electrochemical performance of poly(3-hexylthiophene): Electrospun fibers vs. films

We report on successful preparation of conducting polymer nanofibers from regiorandom poly(3-hexylthiophene). It is shown that the electrochemical properties of obtained structures are significantly improved in course of electrochemical doping process performed in the aqueous phase, moreover this process is accompanied with change of optical properties and water contact angle. These effects are not observed for polymer films. Moreover, doping of nanofibers results in pronounced, irreversible changes in the polymer structure - increased crystallinity due to incorporation of doping ions is confirmed by optical and X-ray crystallographic studies. Ultimately, these changes lead to decreased resistance and improved electrochemical performance of nanofibers mat. As this effect is solely observed for nanofibers of conducting polymer, it can be ascribed to high surface to volume ratio of electrospun fibers mat. Therefore, it is shown for the first time that polythiophene electrochemical doping process effect is dependent on the format of the polymer applied, for nanofibers it can be regarded as attractive method of improving electrochemical properties of polymers. This study received financial support from National Science Centre, NCN, Poland: project OPUS 16: "From ion-selective nanofibers optical and electrochemical sensors towards "lab on a mat"" no. 2018/31/B/ST4/02699.+image