Polyaniline: Application as solid state electrochromic in a flexible textile display

A composite of polyaniline with a flexible nonwoven textile spacer (viscose or PET) has been successfully prepared. Aniline monomer units were initially bound to the surface of the nonwoven substrate and subsequently chemically polymerised in its solid state. The prepared composite was then employed within a flexible four-layer electrochromic device (ECD), previously developed by ourselves. The device consists of the polyaniline–nonwoven composite sandwiched between two electrodes. The lower electrode is silver or carbon black deposited on a flexible PET textile substrate and the upper is flexible and transparent PET/ITO. A reversible colour change of the polyaniline–nonwoven composite is observed, from green to blue, when an electrical voltage (±3 V) is applied to the prepared device. Because polyaniline is used in its solid state it offers an alternative to the liquid state electrochromic previously applied within the developed flexible textile ECD and reduces problems owing to satisfactory sealing and leakage. This paper outlines the preparation and characterisation of the electrochromic polyaniline–nonwoven composite and the electrochromic display prototype in which it is applied. The benefits and drawbacks of the technology are discussed.

► A polyaniline-flexible nonwoven textile spacer composite has been prepared.
► This composite has been employed within a novel flexible electrochromic display.
► A reversible colour change from green to blue is observed when ±3 V is applied.
► The benefits and drawbacks of the technology are discussed.