Investigating MWCNT-graphene interactions via in situ SEM peeling
Horacio Espinosa (Northwestern University), Michael Roenbeck (), Xiaoding Wei (), Allison Beese (), Alona Furmanchuk (), Jeffrey Paci (), George Schatz ()
Symposium in honor of Rod Clifton on the occasion of his 75th Birthday
Mon 2:40 - 4:00
Salomon 101
Recently, the development of carbon nanotube (CNT)-based macroscopic yarns with high strength-to-weight ratios has been an area of great interest within the scientific community. While carbon nanotubes are known for their exceptional mechanical properties, studies to-date have not been able to translate the extraordinary load-bearing capabilities of these nanoscale materials to larger-scale composite and yarns comprised of CNT constituents. Inspirations for bridging this gap in properties can be drawn from nature, which uses structural hierarchies within biomaterials to maximize strength and toughness. Yarns spun from mats of CNTs likewise possess a hierarchical structure that spans across multiple length scales. At the smallest scale, understanding tube-tube interactions is essential for designing high-performance carbon nanotube composites. Here we report an in situ experimental peeling technique that can be used to investigate the adhesion energy between multiwalled carbon nanotubes (MWCNTs) and graphene. In situ scanning electron microscope (SEM) testing enables direct visualization of the nanoscale peeling process which, in turn, provides a means of estimating adhesion energy through classical fracture analysis. The validity of this analysis is substantiated by finite element simulations with boundary conditions derived from experiments. The effective contact width between tubes and graphene is estimated via atomistic simulations. The adhesion energies of bare MWCNT-graphene surfaces are compared to the theoretical value for graphite. This method can serve as a foundation for evaluating the enhancements afforded by chemical functionalization within macroscale CNT-based yarns.