Skip to main content

Hybrid silicone aerogels toward unusual flexibility, functionality, and extended applications


Here, we overview the developments in the past decade made on organic–inorganic hybrid aerogels and xerogels based on silicone (polyorganosiloxanes) through persistent works by the authors to increase the mechanical strength and flexibility and add functionality. Polymethylsilsesquioxane (PMSQ, CH3SiO3/2) has been found to show unusual strength and flexibility against compression, and their bending properties can also be improved by several strategies. Silicone-based networks with organic bridges between inorganic moieties are also beneficial for these improvements. In particular, organic bridges with a higher fraction and more extended length have been found to allow higher durability against large deformations. In addition, functional groups such as vinyl, chloromethyl, and amino can readily be introduced by starting from organoalkoxysilanes with these functional substituents (e.g., FG−Si(OR)3 or (RO)3Si−FG−Si(OR)3, where FG shows an organic substituent containing functional groups and R is typically methyl or ethyl), and other functional groups such as carboxyl can be introduced by post-gelation modifications on the pre-installed FG in the network. Possibilities in applications such as thermal insulators, photoluminescent media, and photocatalysts are also discussed.


  • Silicone-based organic–inorganic hybrid aerogels developed by the authors are overviewed.

  • Improved mechanical flexibility allows ambient pressure drying to yield aerogel-like xerogels.

  • Reactive organic functional groups can be introduced in the hybrid networks.

This is a preview of subscription content, access via your institution.

Scheme 1
Scheme 2
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Scheme 3
Fig. 6
Fig. 7
Fig. 8


  1. 1.

    Brinker CJ, Scherer GW (1990) Sol-gel science: the physics and chemistry of sol-gel processing. Academic Press, San Diego

    Google Scholar 

  2. 2.

    Aegerter MA, Leventis N, Koebel MM (eds) (2011) Aerogels handbook. Springer, New York

    Google Scholar 

  3. 3.

    Soleimani Dorcheh A, Abbasi MH (2008) Silica aerogel; synthesis, properties and characterization. J Mater Process Technol 199:10–26

    Article  Google Scholar 

  4. 4.

    Novak BM, Auerbach D, Verrier C (1994) Low-density, mutually interpenetrating organic-inorganic composite materials via supercritical drying techniques. Chem Mater 6:282–286

    Article  Google Scholar 

  5. 5.

    Ayers MR, Hunt AJ (2001) Synthesis and properties of chitosan-silica hybrid aerogels. J Non-Cryst Solids 285:123–127

    Article  Google Scholar 

  6. 6.

    Leventis N, Sotiriou-Leventis C, Zhang G, Rawashdeh A-MM (2002) Nanoengineering strong silica aerogels. Nano Lett 2:957–960

    Article  Google Scholar 

  7. 7.

    Venkateswara Rao A, Bhagat SD, Hirashima H, Pajonk GM (2006) Synthesis of flexible silica aerogels using methyltrimethoxysilane (MTMS) precursor. J Colloid Interface Sci 300:279–285

    Article  Google Scholar 

  8. 8.

    Boday DJ, Stover RJ, Muriithi B, Loy DA (2012) Mechanical properties of hexylene- and phenylene-bridged polysilsesquioxane aerogels and xerogels. J Sol-Gel Sci Technol 61:144–150

    Article  Google Scholar 

  9. 9.

    Kanamori K, Nakanishi K (2011) Controlled pore formation in organotrialkoxysilane-derived hybrids: from aerogels to hierarchically porous monoliths. Chem Soc Rev 40:754–770

    Article  Google Scholar 

  10. 10.

    Shimizu T, Kanamori K, Nakanishi K (2017) Silicone-based organic–inorganic hybrid aerogels and xerogels. Chem Eur J 23:5176–5187

    Article  Google Scholar 

  11. 11.

    Kanamori K, Aizawa M, Nakanishi K, Hanada T (2007) New transparent methylsilsesquioxane aerogels and xerogels with improved mechanical properties. Adv Mater 19:1589–1593

    Article  Google Scholar 

  12. 12.

    Venkateswara Rao A, Pajonk GM (2001) Effect of methyltrimethoxysilane as a co-precursor on the optical properties of silica aerogels. J Non Cryst Solids 285:202–209

    Article  Google Scholar 

  13. 13.

    Hayase G, Kanamori K, Nakanishi K (2012) Structure and properties of polymethylsilsesquioxane aerogels synthesized with surfactant n-hexadecyltrimethylammonium chloride. Microporous Mesoporous Mater 158:247–252

    Article  Google Scholar 

  14. 14.

    Kurahashi M, Kanamori K, Takeda K, Kaji H, Nakanishi K (2012) Role of block copolymer surfactant on the pore formation in methylsilsesquioxane aerogel systems. RSC Adv 2:7166–7173

    Article  Google Scholar 

  15. 15.

    Hayase G, Kanamori K, Maeno A, Kaji H, Nakanishi K (2016) Dynamic spring-back behavior in evaporative drying of polymethylsilsesquioxane monolithic gels for low-density transparent thermal superinsulators. J Non Cryst Solids 434:115–119

    Article  Google Scholar 

  16. 16.

    Smith DM, Stein D, Anderson JM, Ackerman W (1995) Preparation of low-density xerogels at ambient pressure. J Non Cryst Solids 186:104–112

    Article  Google Scholar 

  17. 17.

    Liu C (2007) Recent developments in polymer MEMS. Adv Mater 19:3783–3790

    Article  Google Scholar 

  18. 18.

    Duan G, Jiang S, Moss T, Agarwal S, Greiner A (2016) Ultralight open cell polymer sponges with advanced properties by PPX CVD coating. Polym Chem 7:2759–2764

    Article  Google Scholar 

  19. 19.

    Hayase G, Kanamori K, Nakanishi K (2011) New flexible aerogels and xerogels derived from methyltrimethoxysilane/dimethyldimethoxysilane co-precursors. J Mater Chem 21:17077–17079

    Article  Google Scholar 

  20. 20.

    Hayase G, Kanamori K, Fukuchi M, Kaji H, Nakanishi K (2013) Facile synthesis of marshmallow-like macroporous gels usable under harsh conditions for the separation of oil and water. Angew Chem Int Ed 52:1986–1989

    Article  Google Scholar 

  21. 21.

    Hayase G, Kanamori K, Hasegawa G, Maeno A, Kaji H, Nakanishi K (2013) A superamphiphobic macroporous silicone monolith with marshmallow-like flexibility. Angew Chem Int Ed 52:10788–10791

    Article  Google Scholar 

  22. 22.

    Hayase G, Kanamori K, Abe K, Yano H, Maeno A, Kaji H, Nakanishi K (2014) Polymethylsilsesquioxane-cellulose nanofiber biocomposite aerogels with high thermal insulation, bendability, and superhydrophobicity. ACS Appl Mater Interfaces 6:9466–9471

    Article  Google Scholar 

  23. 23.

    Kobayashi Y, Saito T, Isogai A (2014) Aerogels with 3D ordered nanofiber skeletons of liquid-crystalline nanocellulose derivatives as tough and transparent insulators. Angew Chem Int Ed Engl 53:10394–10397

    Article  Google Scholar 

  24. 24.

    Takeshita S, Yoda S (2015) Chitosan aerogels: transparent, flexible thermal insulators. Chem Mater 27:7569–7572

    Article  Google Scholar 

  25. 25.

    Aoki Y, Shimizu T, Kanamori K, Maeno A, Kaji H, Nakanishi K (2017) Low-density, transparent aerogels and xerogels based on hexylene-bridged polysilsesquioxane with bendability. J Sol-Gel Sci Technol 81:42–51

    Article  Google Scholar 

  26. 26.

    Shimizu T, Kanamori K, Maeno A, Kaji H, Nakanishi K (2016) Transparent ethylene-bridged polymethylsiloxane aerogels and xerogels with improved bending flexibility. Langmuir 32:13427–13434

    Article  Google Scholar 

  27. 27.

    Shimizu T, Kanamori K, Maeno A, Kaji H, Doherty CM (2017) Transparent ethenylene-bridged polymethylsiloxane aerogels: mechanical flexibility and strength and availability for addition reaction. Langmuir 33:4543–4550

    Article  Google Scholar 

  28. 28.

    Shimizu T, Kanamori K, Maeno A, Kaji H, Doherty CM, Falcaro P, Nakanishi K (2016) Transparent, highly insulating polyethyl- and polyvinylsilsesquioxane aerogels: mechanical improvements by vulcanization for ambient pressure drying. Chem Mater 28:6860–6868

    Article  Google Scholar 

  29. 29.

    Zu G, Shimizu T, Kanamori K, Zhu Y, Maeno A, Kaji H, Shen J, Nakanishi K (2018) Transparent, superflexible doubly cross-linked polyvinylpolymethylsiloxane aerogel superinsulators via ambient pressure drying. ACS Nano 12:521–532

    Article  Google Scholar 

  30. 30.

    Gunji T, Okonogi H, Sakan T, Takamura N, Arimitsu K, Abe Y (2003) Preparation and properties of organic–inorganic hybrid gel films based on polyvinylpolysilsesquioxane synthesized from trimethoxy(vinyl)silane. Appl Organo Chem 17:580–588

    Article  Google Scholar 

  31. 31.

    Gunji T, Kawaguchi Y, Okonogi H, Sakan T, Arimitsu K, Abe Y (2005) Preparation and properties of organic-inorganic hybrid gel films based on polyvinylpolysilsesquioxane synthesized from trimethoxy(vinyl)silane. J Sol-Gel Sci Technol 33:9–13

    Article  Google Scholar 

  32. 32.

    Zu G, Kanamori K, Shimizu T, Zhu Y, Maeno A, Kaji H, Nakanishi K, Shen J (2018) A versatile double-crosslinking approach to transparent, machinable, super-compressible, highly bendable aerogel thermal superinsulators Chem Mater 30:2759–2770

    Article  Google Scholar 

  33. 33.

    Sanda S, Kanamori K, Takei T, Tashiro K (2018) Aerogel photocatalyst composed of transparent mesoporous polymethylsilsesquioxane softly post-modified with a visible-light-absorbing metal complex. ChemNanoMat 4:52–55

    Article  Google Scholar 

  34. 34.

    Shimizu T, Kanamori K, Nakanishi K (2017) Transparent polyvinylsilsesquioxane aerogels: investigations on synthetic parameters and surface modification. J Sol-Gel Sci Technol 82:2–14

    Article  Google Scholar 

  35. 35.

    Ketelson HA, Brook MA, Pelton RH (1995) Sterically stabilized silica colloids: radical grafting of poly(methyl methacrylate) and hydrosilylative grafting of silicones to functionalized silica. Polym Adv Technol 6:335–344

    Article  Google Scholar 

  36. 36.

    Cicero RL, Linford MR, Chidsey CED (2000) Photoreactivity of unsaturated compounds with hydrogen-terminated silicon(111). Langmuir 16:5688–5695

    Article  Google Scholar 

  37. 37.

    Kimura T, Shimizu T, Kanamori K, Maeno A, Kaji H, Nakanishi K (2017) Aerogels from chloromethyltrimethoxysilane and their functionalizations. Langmuir 33:13841–13848

    Article  Google Scholar 

  38. 38.

    Dong Y, Wang R, Li H, Shao J, Chi Y, Lin X, Chen G (2012) Polyamine-functionalized carbon quantum dots for chemical sensing. Carbon N Y 50:2810–2815

    Article  Google Scholar 

  39. 39.

    Keppeler M, Hüsing N (2011) Space-confined click reactions in hierarchically organized silica monoliths. New J Chem 35:681

    Article  Google Scholar 

  40. 40.

    Meador MAB, Fabrizio EF, Ilhan F, Dass A, Zhang G, Vassilaras P, Johnston JC, Leventis N (2005) Cross-linking amine-modified silica aerogels with epoxies: mechanically strong lightweight porous materials. Chem Mater 17:1085–1098

    Article  Google Scholar 

  41. 41.

    Cui S, Cheng W, Shen X, Fan M, Russell A, Wu Z, Yi X (2011) Mesoporous amine-modified SiO2 aerogel: a potential CO2 sorbent. Energy Environ Sci 4:2070–2074

  42. 42.

    Boury B, Corriu JP (2002) Auto-organisation of hybrid organic–inorganic materials prepared by sol–gel process. Chem Commun 8:795–802

  43. 43.

    Kramer SJ, Rubio-Alonso F, Mackenzie JD (1996) Organically modified silicate aerogels, ‘aeromosils’. Mater Res Soc Symp Proc 435:295–300

    Article  Google Scholar 

  44. 44.

    Hüsing N, Schubert I (1997) Organofunctional silica aerogels. J Sol-Gel Sci Technol 8:807–812

    Google Scholar 

Download references


This study has been performed under financial supports from Advanced Low Carbon Technology Research and Development Program (ALCA, Japan Science and Technology Agency) and JSPS KAKENHI Grant Number 17K06015.

Author information



Corresponding author

Correspondence to Kazuyoshi Kanamori.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kanamori, K., Ueoka, R., Kakegawa, T. et al. Hybrid silicone aerogels toward unusual flexibility, functionality, and extended applications. J Sol-Gel Sci Technol 89, 166–175 (2019).

Download citation


  • Organic–inorganic hybrid
  • Silicone
  • Aerogel
  • Xerogel
  • Mechanical property
  • Functionality