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Toughening of nanoporous glasses using porogen residuals

Nature Materials volume 3, pages 464–469 (2004)Cite this article

Abstract

Nanoporous glasses are inherently brittle materials that become increasingly fragile with increasing porosity. We show that remarkable increases in fracture energy can be obtained from remnants of the porogen molecules used to create the nanoscale pores. The interfacial fracture energy of ∼2.6 J m−2 for dense methylsilsesquioxane glass films is shown to increase by over one order of magnitude to >30 J m−2 for glasses containing 50 vol.% porosity. The increased fracture resistance is related to a powerful molecular-bridging mechanism that was modelled using bridging mechanics. The study demonstrates that significant increases in interfacial fracture energy may be obtained using strategies involving controlled decomposition of the porogen molecule during processing of nanoporous glasses. The implications are important for a range of emerging optical, electronic and biological technologies that use nanoporous thin films, but are limited by the degradation of mechanical properties with increasing porosity.

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Figure 1: Illustration of the thin-film structure containing the nanoporous MSSQ layer.
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Figure 5: Characterization of the fracture surfaces adjacent to the MSSQ-LO films, which debonded along the MSSQ/SiO2 interface.

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Acknowledgements

Work was supported primarily by a seed grant from the Stanford-CPIMA MRSEC Program of the National Science Foundation under Award Number DMR -0213618.

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Authors and Affiliations

  1. Department of Materials Science and Engineering, Stanford University, 416 Escondido Mall, Stanford, 94305-2205, California, USA

    Daniel A. Maidenberg & Reinhold H. Dauskardt

  2. IBM-Almaden Research Center, 650 Harry Road, San Jose, 95120-6099, California, USA

    Willi Volksen & Robert D. Miller

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  1. Daniel A. Maidenberg
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  2. Willi Volksen
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Correspondence to Reinhold H. Dauskardt.

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Maidenberg, D., Volksen, W., Miller, R. et al. Toughening of nanoporous glasses using porogen residuals. Nature Mater 3, 464–469 (2004). https://doi.org/10.1038/nmat1153

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