Here we report a combined study of experiments and simulations to understand how chemical functional groups can mechanically stabilize aggregates of carbon nanotubes (CNTs). Ultralow density aggregates of chemically functionalized CNTs, in the form of macro-scale spheres made by freeze-drying method, show mechanical stabilization and near complete elastic recovery during deformation. Simulations of interacting functionalized carbon nanotube aggregates show better structural retention compared to non-functionalized CNTs under compression, suggesting that the atomic-level interactions between functional groups on adjoining CNTs help maintain structural rigidity and elastic response during loading. Aggregates of non-functionalized CNTs collapses under similar loading conditions. The dynamic mechanical responses of CNT macrostructures and mechano-chemical stabilization are directly observed using in-situ deformation inside a scanning electron microscope.
Mechano-chemical stabilization of three-dimensional carbon nanotube aggregates
In the current work, we report an easily scalable method of synthesizing 3D foam into spheres with millimeter to micrometer scales made up entirely of functionalized CNTs exhibiting completely elastic behavior until a high strain. An in-situ mechanical system attached to a high resolution SEM has been used to conduct quasi-static uniaxial compression on the individual building blocks and macroscopic sphere. The complete elastic behavior of these CNT spheres is further explained with help of detailed molecular dynamics (MD) simulations. The simulations addressed the role of functional groups in such kind of behavior.