Degradation behavior of free-standing polypyrrole films in NaOH solution. (February 2019)

• Record Type: Journal Article
• Authors: Jin, Zhenzhen; Qi, Kai; Qiu, Yubing; Chen, Zhenyu; Guo, Xingpeng
• Is Part Of: Polymer degradation and stability. Volume 160(2019)
• Page Start: 60
• Page End: 72
• Publication Date: 2019-02
• Subjects: Free-standing polypyrrole -- Degradation behavior -- NaOH solution -- Film thickness -- Electrochemical activity; Polymers -- Deterioration -- Periodicals; Stabilizing agents -- Periodicals; Polymères -- Dégradation -- Périodiques; Stabilisants -- Périodiques; 668.9
• DOI: 10.1016/j.polymdegradstab.2018.12.009
• Languages: English
• ISSNs: 0141-3910

Abstract

Abstract: Free-standing polypyrrole (PPy) films hold promising potential in flexible energy storage devices, actuators, and artificial muscles, but they are limited by service failure. In this work, free-standing PPy/p-toluenesulfonate (PPy/pTS) films with different thickness (1.8 and 4.2 μm) were prepared, and their degradation behavior in aerated and de-aerated 0.5 M NaOH was investigated to make clear the changes of chemical and electrochemical degradation processes on free-standing PPy films. The degradation of electrochemical activity of the free-standing PPy film leads to an obvious increase in its internal resistance and shows similar kinetics as the PPy film with a Pt substrate, i.e. one degradation stage and its rate follows first-order kinetics. The degradation rate constant ( k ) in aerated NaOH increases largely owing to the existence of the dominant electrochemical degradation process. The k value of the thick film (4.2 μm) decreases obviously resulting from a more ordered and compact structure, which limits ion diffusion in the polymer matrix so as to greatly inhibit the chemical degradation process. The free-standing PPy film shows lower electrochemical activity and much larger k values compared with the PPy film with a Pt substrate under the same condition. The mechanisms involved were discussed. Highlights: . Degradation of free-standing PPy/pTS films (1.8 and 4.2 μm) is studied. . Degradation of free-standing PPy films increases its internal resistance obviously. . One degradation stage is shown and its rate follows first-order kinetics. . Thick free-standing PPy films show much smaller degradation rate constants.