Characterization of Aniline Tetramer by MALDI TOF Mass Spectrometry upon Oxidative and Reductive Cycling

Rebecca L Li; Cheng-Wei Lin; Yuanlong Shao; Che Wei Chang; Fu-Kai Yao; Matthew D Kowal; Haosen Wang; Michael T Yeung; Shu-Chuan Huang; Richard B Kaner

doi:10.3390/polym8110401

Characterization of Aniline Tetramer by MALDI TOF Mass Spectrometry upon Oxidative and Reductive Cycling

Polymers (Basel). 2016 Nov 15;8(11):401. doi: 10.3390/polym8110401.

Authors

Rebecca L Li¹, Cheng-Wei Lin², Yuanlong Shao³, Che Wei Chang⁴, Fu-Kai Yao⁵, Matthew D Kowal⁶, Haosen Wang⁷, Michael T Yeung⁸, Shu-Chuan Huang⁹, Richard B Kaner^{10

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Affiliations

¹ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. rebeccali@ucla.edu.
² Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. chengweilin@g.ucla.edu.
³ Cambridge Graphene Centre, Cambridge University, Cambridge CB3 0FA, UK. ys461@cam.ac.uk.
⁴ Department of Chemistry, National Dong Hwa University, Hualien 97401, Taiwan. robin780115@hotmail.com.
⁵ Department of Chemistry, National Dong Hwa University, Hualien 97401, Taiwan. sym23528@hotmail.com.
⁶ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. mdkowal@gmail.com.
⁷ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. whs19890924@gmail.com.
⁸ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. tyrone@chem.ucla.edu.
⁹ Department of Chemistry, National Dong Hwa University, Hualien 97401, Taiwan. schuang@mail.ndhu.edu.tw.
¹⁰ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. kaner@chem.ucla.edu.
¹¹ Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, USA. kaner@chem.ucla.edu.

Abstract

By combining electrochemical experiments with mass spectrometric analysis, it is found that using short chain oligomers to improve the cycling stability of conducting polymers in supercapacitors is still problematic. Cycling tests via cyclic voltammetry over a potential window of 0 to 1.0 V or 0 to 1.2 V in a two-electrode device configuration resulted in solid-state electropolymerization and chain scission. Electropolymerization of the aniline tetramer to generate long chain oligomers is shown to be possible despite the suggested decrease in reactivity and increase in intermediate stability with longer oligomers. Because aniline oligomers are more stable towards reductive cycling when compared to oxidative cycling, future conducting polymer/oligomer-based pseudocapacitors should consider using an asymmetric electrode configuration.

Keywords: conducting polymers; degradation mechanism; mass spectroscopy; oligomers; supercapacitors.

Grants and funding

CBET 1337065/NSF