Journal
ADVANCED ENGINEERING MATERIALS
Volume 13, Issue 10, Pages B405-B414Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/adem.201080113
Keywords
-
Categories
Funding
- Army Research Office [W9-11NNF-06-1029]
- Gates Millennium Scholars Program
- National Science Foundation
- Department of Civil and Environmental Engineering at the Massachusetts Institute of Technology
- Piemonte grant Metrology on a cellular and macromolecular scale for regenerative medicine''-METREGEN
Ask authors/readers for more resources
Biology implements intriguing structural design principles that allow for attractive mechanical properties-such as high strength, toughness, and extensibility despite being made of weak and brittle constituents, as observed in biomineralized structures. For example, diatom algae contain nanoporous hierarchical silicified shells, called frustules, which provide mechanical protection from predators and virus penetration. These frustules generally have a morphology resembling honeycombs within honeycombs, meshes, or wavy shapes, and are surprisingly tough when compared to bulk silica, which is one of the most brittle materials known. However, the reason for its extreme extensibility has not been explained from a molecular level upwards. By carrying out a series of molecular dynamics simulations with the first principles-based reactive force field ReaxFF, the mechanical response of the structures is elucidated and correlated with underlying deformation mechanisms. Specifically, it is shown that for wavy silica, unfolding mechanisms are achieved for increasing amplitude and allow for greater ductility of up to 270% strain. This mechanism is reminiscent to the uncoiling of hidden length from proteins that allows for enhanced energy dissipation capacity and, as a result, toughness. We report the development of an analytical continuum model that captures the results from atomistic simulations and can be used in multiscale models to bridge to larger scales. Our results demonstrate that tuning the geometric parameters of amplitude and width in wavy silica nanostructures are beneficial in improving the mechanical properties, including enhanced deformability, effectively overcoming the intrinsic shortcomings of the base material that features extreme brittleness.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available