A new chromic (TouchChromic) thin film

作者：Ram Manoj K; Goswami D Yogi; Takshi Arash; Stefanakos Elias^*

来源：Acta Materialia, 2016, 121: 325-330.

DOI：10.1016/j.actamat.2016.09.019

• Chromic
• TouchChromic
• Conducting polymer
• Electrolyte
• Composite
• Coloration
• Metal

We present an exciting new development in thin films which enables innovative reversible color change in the film when touched by a metal without any external excitation, i.e. voltage, temperature, light, etc. The thin film structure is simpler than that of electrochromic materials, requiring only a nanocomposite of a conducting polymer and a gel electrolyte deposited on a transparent conductive substrate (TO, ITO, FTO, etc.) These smart nanocomposite thin films, we can call TouchChromic, can be used in windows (i.e., opaque to transparent) and in a number of other applications such as rear view mirrors in vehicles, IR sensors, toys, and camouflage for the military and defense sectors. The color change and color contrast depend on the type of film, its thickness and composition of the electrolyte. For aqueous acidic electrolytes, a molality of less than 0.01 was found to be most effective. The addition of an oxidizer (i.e. ammonium persulfate) in the electrolytic solution increased the speed of color change. The color change occurs only when specific metals touch the electrolyte. Detailed experimental and theoretical results are presented in this paper to explain the behavior of the chromic film in terms of the pH of the electrolyte, work functions (Fermi levels) of corresponding layers (transparent substrate, conductive polymer, electrolyte and metal) and the energy band diagram of the composite structure.

• 出版日期2016-12