Counterion-induced reversibly switchable transparency in smart windows

Chang Hwan Lee, Ho Sun Lim, Jooyong Kim, Jeong Ho Cho

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Smart windows that can reversibly alternate between extreme optical characteristics via clicking counteranions of different hydration energies were developed on glass substrates through the facile spray-casting of poly[2-(methacryloyloxy)ethyltrimethylammonium chloride-co-3-(trimethoxysilyl) propyl methacrylate]. The optical transmittance was either 90.9% or 0% over the whole spectral range when alternately immersed in solutions containing thiocyanate (SCN-) or bis(trifluoromethane)sulfonimide (TFSI -) ions, respectively. The extreme optical transitions were attributed to formation of microporous structures via the molecular aggregation of polyelectrolyte chains bearing TFSI- ions in methanol. Because the smart windows were either highly transparent toward or completely blocking of incident light upon direct counterion exchange, this kind of nanotechnology may provide a new platform for efficiently conserving on energy usage in the interior of buildings.

Original languageEnglish
Pages (from-to)7397-7403
Number of pages7
JournalACS Nano
Issue number9
Publication statusPublished - 2011 Sept 27

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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