am8b09878_si_001.pdf (1.67 MB)
Fast Switching Properties and Ion Diffusion Behavior of Polytriphenylamine Derivative with Pendent Ionic Liquid Unit
journal contribution
posted on 2018-09-04, 00:00 authored by Liang Qian, Xiaojing Lv, Mi Ouyang, Alexey Tameev, Konstantin Katin, Mikhail Maslov, Qian Bi, Conghui Huang, Rui Zhu, Cheng ZhangA novel
triphenylamine derivative-linked ionic liquid unit, 1-(6-((4-(bis(4-(thiophen-2-yl)phenyl)amino)benzoyl)oxy)hexyl)-3-methyl-imidazolium
tetrafluoroborate (TTPAC6IL-BF4), was designed
and synthesized successfully, and its corresponding polymer PTTPAC6IL-BF4 was obtained by the electropolymerization
method. The highest occupied molecular orbital energy band of TTPAC6IL-BF4 is higher and the onset oxidative potential
lower compared with that of 6-bromohexyl 4-(bis(4-(thiophen-2-yl)phenyl)amino)
benzoate (TTPAC6Br) without modifying the ionic liquid
unit. Both PTTPAC6IL-BF4 and PTTPAC6Br show similar color change and optical contrast under different
redox states. However, PTTPAC6IL-BF4 presents
a faster electrochromic switching time than PTTPAC6Br owing
to the improved ionic conductivity and ion diffusion coefficient with
the introduction of a pendent ionic liquid unit. It is more intriguing
that PTTPAC6IL-BF4 could show electrochromism
under different potentials even without supplying any additional electrolyte.
The particular behavior further proves that BF4– ions around imidazole cations at the side chain may participate
in balancing the charge of the polymer backbone when redox reaction
happens, resulting in faster movement of ions during the doping process.
The results imply that introducing an ionic liquid unit to the side
chain is an efficient method to improve the switching time of conjugated
polymers and would be inspirational for the design and preparation
of novel bifunctional electrochromic polymeric electrolytes.