Flexible Transparent Aerogels as Window Retrofitting Films and Optical Elements with Tunable Birefringence

Ronggui Yang, Qingkun Liu, Allister Frazier, Xinpeng Zhao, Joshua De La Cruz, Andrew Hess, Ivan Smalyukh

Research output: Contribution to journalArticlepeer-review

67 Scopus Citations


Experimental realization of optically transparent, mechanically robust and flexible aerogels has been a longstanding challenge, which limits their practical applications in energy-saving devices, such as thermally insulating films for enhancing energy efficiency of windows. The poor transparency precluded even hypothetical consideration of the possibility of birefringent aerogels. We develop birefringent and optically isotropic aerogels that combine properties of thermal super-insulation, mechanical robustness and flexibility, and transparency to visible-spectrum light. This unusual combination of physical properties is achieved by combining liquid crystalline self-organization of cellulose nanofibers with polysiloxane cross-linking and control of the nanoscale porosity to form hybrid organic-inorganic mesostructured aerogels. Potential applications of these inexpensive materials range from single pane window retrofitting to smart fabrics.
Original languageAmerican English
Pages (from-to)266-274
Number of pages9
JournalNano Energy
StatePublished - 2018

NREL Publication Number

  • NREL/JA-5500-71320


  • aerogel
  • cellulose nanofiber
  • liquid crystal
  • thermal insulation
  • transparent


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