title: Indentation Tests Reveal Geometry-Regulated Stiffening of Nanotube Junctions.
abstract: Here we report a unique method to locally determine the mechanical response of individual covalent junctions between carbon nanotubes (CNTs), in various configurations such as "X", "Y", and "Λ"-like. The setup is based on in situ indentation using a picoindenter integrated within a scanning electron microscope. This allows for precise mapping between junction geometry and mechanical behavior and uncovers geometry-regulated junction stiffening. Molecular dynamics simulations reveal that the dominant contribution to the nanoindentation response is due to the CNT walls stretching at the junction. Targeted synthesis of desired junction geometries can therefore provide a "structural alphabet" for construction of macroscopic CNT networks with tunable mechanical response.
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Sehmus
authors.initials: S
authors.lastname: Ozden
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Chandra Sekhar
authors.initials: CS
authors.lastname: Tiwary
authors.affiliation: Hysitron, Inc. , Minneapolis, Minnesota 55344, United States.
authors.forename: Sanjit
authors.initials: S
authors.lastname: Bhowmick
authors.affiliation: Hysitron, Inc. , Minneapolis, Minnesota 55344, United States.
authors.forename: Syed
authors.initials: S
authors.lastname: Asif
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Evgeni S
authors.initials: ES
authors.lastname: Penev
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Boris I
authors.initials: BI
authors.lastname: Yakobson
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
keywords: Carbon nanotube junctions; atomistic modeling; in situ nanoindentation