Journal of Sol-Gel Science and Technology

, Volume 81, Issue 1, pp 42–51

Low-density, transparent aerogels and xerogels based on hexylene-bridged polysilsesquioxane with bendability

  • Yosuke Aoki
  • Taiyo Shimizu
  • Kazuyoshi Kanamori
  • Ayaka Maeno
  • Hironori Kaji
  • Kazuki Nakanishi
Original Paper: Nano- and macroporous materials (aerogels, xerogels, cryogels, etc.)

Abstract

Low-density, transparent aerogels based on a hexylene-bridged polysilsesquioxane ([O1.5Si–(CH2)6–SiO1.5]n) network have been prepared for the first time via a simple sol–gel process. An optimized base-catalyzed one-step hydrolysis–polycondensation process of a bridged alkoxysilane precursor 1,6-bis(trimethoxysilyl)hexane in a low-polarity solvent N,N-dimethylformamide allows for the formation of a pore structure of a length scale of several tens nanometers, resulting in low-density, transparent aerogels after supercritical drying. Because of the incorporated organic moiety that bridges the silicon atoms in the network, these aerogels show higher flexibility and strength against compression and bending as compared to silica aerogel counterparts. In addition, minimizing the residual silanol groups in the network by a surface modification with hexamethyldisilazane has further improved resilience after compression and bending flexibility and strength, due to the decreased chance of the irreversible formation of the siloxane bonds upon compression. The resulting trimethylsilylated hydrophobic gels have been subjected to ambient pressure drying to obtain xerogels, resulting in low-density (0.13 g cm−3, 90 % porosity), transparent (71 % transmittance) xerogels. These results are promising for the development of transparent thermal superinsulators applicable to window insulating systems that manage heat transfer in a more efficient way.

Graphical Abstract

Keywords

Bridged polysilsesquioxane Hexylene Aerogels Xerogels Optical and mechanical properties 

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Yosuke Aoki
    • 1
  • Taiyo Shimizu
    • 1
  • Kazuyoshi Kanamori
    • 1
  • Ayaka Maeno
    • 2
  • Hironori Kaji
    • 2
  • Kazuki Nakanishi
    • 1
  1. 1.Department of Chemistry, Graduate School of ScienceKyoto UniversitySakyo-kuJapan
  2. 2.Division of Environmental Chemistry, Institute for Chemical ResearchKyoto UniversityGokasho, UjiJapan

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