title: Compression behavior of single-layer graphenes.
abstract: Central to most applications involving monolayer graphenes is its mechanical response under various stress states. To date most of the work reported is of theoretical nature and refers to tension and compression loading of model graphenes. Most of the experimental work is indeed limited to the bending of single flakes in air and the stretching of flakes up to typically approximately 1% using plastic substrates. Recently we have shown that by employing a cantilever beam we can subject single graphenes to various degrees of axial compression. Here we extend this work much further by measuring in detail both stress uptake and compression buckling strain in single flakes of different geometries. In all cases the mechanical response is monitored by simultaneous Raman measurements through the shift of either the G or 2D phonons of graphene. Despite the infinitely small thickness of the monolayers, the results show that graphenes embedded in plastic beams exhibit remarkable compression buckling strains. For large length (l)-to-width (w) ratios (> or =0.2) the buckling strain is of the order of -0.5% to -0.6%. However, for l/w < 0.2 no failure is observed for strains even higher than -1%. Calculations based on classical Euler analysis show that the buckling strain enhancement provided by the polymer lateral support is more than 6 orders of magnitude compared to that of suspended graphene in air.
authors.affiliation: Institute of Chemical Engineering and High Temperature Chemical Processes, Foundation of Research and Technology-Hellas (FORTH/ICE-HT), Patras, Greece.
authors.forename: Otakar
authors.initials: O
authors.lastname: Frank
authors.forename: Georgia
authors.initials: G
authors.lastname: Tsoukleri
authors.forename: John
authors.initials: J
authors.lastname: Parthenios
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Papagelis
authors.forename: Ibtsam
authors.initials: I
authors.lastname: Riaz
authors.forename: Rashid
authors.initials: R
authors.lastname: Jalil
authors.forename: Kostya S
authors.initials: KS
authors.lastname: Novoselov
authors.forename: Costas
authors.initials: C
authors.lastname: Galiotis
mesh_terms: D019245:Compressive Strength; D003198:Computer Simulation; D055119:Elastic Modulus; D006108:Graphite / Q000737:chemistry*; D006244:Hardness; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008956:Models, Chemical; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D008567:Membranes, Artificial; D006108:Graphite