title: Unusually Large Young's Moduli of Amino Acid Molecular Crystals.
abstract: Young's moduli of selected amino acid molecular crystals were studied both experimentally and computationally using nanoindentation and dispersion-corrected density functional theory. The Young modulus is found to be strongly facet-dependent, with some facets exhibiting exceptionally high values (as large as 44 GPa). The magnitude of Young's modulus is strongly correlated with the relative orientation between the underlying hydrogen-bonding network and the measured facet. Furthermore, we show computationally that the Young modulus can be as large as 70-90 GPa if facets perpendicular to the primary direction of the hydrogen-bonding network can be stabilized. This value is remarkably high for a molecular solid and suggests the design of hydrogen-bond networks as a route for rational design of ultra-stiff molecular solids.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 (Israel).
authors.forename: Ido
authors.initials: I
authors.lastname: Azuri
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 (Israel).
authors.forename: Elena
authors.initials: E
authors.lastname: Meirzadeh
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 (Israel).
authors.forename: David
authors.initials: D
authors.lastname: Ehre
authors.affiliation: Chemical Research Support, Weizmann Institute of Science, Rehovoth 76100 (Israel).
authors.forename: Sidney R
authors.initials: SR
authors.lastname: Cohen
authors.affiliation: The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323 (USA).
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Rappe
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 (Israel).
authors.forename: Meir
authors.initials: M
authors.lastname: Lahav
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 (Israel). Igor.Lubomirsky@weizmann.ac.il.
authors.forename: Igor
authors.initials: I
authors.lastname: Lubomirsky
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100 (Israel). leeor.kronik@weizmann.ac.il.
authors.forename: Leeor
authors.initials: L
authors.lastname: Kronik
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D055119:Elastic Modulus; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011789:Quantum Theory; D013314:Stress, Mechanical
chemical_list: D000596:Amino Acids
keywords: Young’s modulus; amino acids; crystallography; density functional calculations; mechanical properties