title: Molecular-Level Engineering of Adhesion in Carbon Nanomaterial Interfaces.
abstract: Weak interfilament van der Waals interactions are potentially a significant roadblock in the development of carbon nanotube- (CNT-) and graphene-based nanocomposites. Chemical functionalization is envisioned as a means of introducing stronger intermolecular interactions at nanoscale interfaces, which in turn could enhance composite strength. This paper reports measurements of the adhesive energy of CNT-graphite interfaces functionalized with various coverages of arylpropionic acid. Peeling experiments conducted in situ in a scanning electron microscope show significantly larger adhesive energies compared to previously obtained measurements for unfunctionalized surfaces (Roenbeck et al. ACS Nano 2014, 8 (1), 124-138). Surprisingly, however, the adhesive energies are significantly higher when both surfaces have intermediate coverages than when one surface is densely functionalized. Atomistic simulations reveal a novel functional group interdiffusion mechanism, which arises for intermediate coverages in the presence of water. This interdiffusion is not observed when one surface is densely functionalized, resulting in energy trends that correlate with those observed in experiments. This unique intermolecular interaction mechanism, revealed through the integrated experimental-computational approach presented here, provides significant insights for use in the development of next-generation nanocomposites.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Roenbeck
authors.forename: Al'ona
authors.initials: A
authors.lastname: Furmanchuk
authors.forename: Zhi
authors.initials: Z
authors.lastname: An
authors.affiliation: ⊥Department of Chemistry, University of Victoria, British Columbia V8W 3V6, Canada.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Paci
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Wei
authors.forename: SonBinh T
authors.initials: ST
authors.lastname: Nguyen
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
authors.forename: Horacio D
authors.initials: HD
authors.lastname: Espinosa
keywords: Carbon-based nanomaterials; adhesive energy; atomistic simulations; chemical functionalization; in situ SEM testing; surface energy