Triazole-based ionene exhibiting tunable structure and ionic conductivity obtained via cycloaddition reaction: A new polyelectrolyte for electrochromic devices

• Published in: Solar energy materials and solar cells 2018-12, Vol.188, p.210-218
• Main Authors: Puguan, John Marc C., Boton, Lilian B., Kim, Hern
• Format: Article
• Language: English
• Subjects: 1,2,3-triazole; Alkynes; Anion exchanging; Azide; Bleaching; Conductivity; CuAAC; Cycloaddition; Electrochemistry; Electrochromic cells; Electrochromic devices; Electrochromism; Electrolytes; Energy efficiency; Ethylene; Ethylene oxide; Fluorination; Halides; Ion currents; Ionene; Ionenes; Ionic liquids; Polyelectrolyte; Polyelectrolytes; Polyethylene oxide; Salts; Smart materials; Smart windows; Switches; Thermal properties; Thermodynamic properties; Trifluoromethane
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2018.09.009

Main-chain poly(ionic liquid)s based on 1,2,3-triazole with pentaoxyethylene spacer was developed via copper-catalyzed alkyne-azide cycloaddition (CuAAC) of a novel azide/alkyne-terminal monomer and subsequently quaternized by alkyl halides followed by anion exchanges with several fluorinated salts. Introduction of the extended ethylene oxide fragments [–(CH2CH2O)5–] has made this new PIL with methyl substituent and bis(trifluoromethane)sulfonimide counteranion exhibit ionic conductivity of 1.16 × 10−4 S cm−1 at 30 °C. This new electrolyte efficiently switches an electrochromic device (ECD) with 18% optical contrast from its transparent state to a colored state in 4.75 s and while bleaching takes 11.8 s. The development of this polyelectrolyte with simple structure and excellent physical and thermal properties is promising for the design of new all-solid state energy efficient smart windows and devices and other electrochemical device applications. •Ionene with pentaoxyethylene spacer was synthesized via cycloaddition reaction.•[–(CH2CH2O)5–] fragments on the main chain enhanced the PIL's ionic conductivity.•Easy tunability of ionic conductivity and structure of ionenes.•New series of PILs exhibit excellent thermal and mechanical properties.•Fabricated ECD which efficiently switches from bleached to colored state.