title: Morphological and mechanical characterization of composite calcite/SWCNT-COOH single crystals.
abstract: A growing number of classes of organic (macro)molecular materials have been trapped into inorganic crystalline hosts, such as calcite single crystals, without significantly disrupting their crystalline lattices. Inclusion of an organic phase plays a key role in enhancing the mechanical properties of the crystals, which are believed to share structural features with biogenic minerals. Here we report the synthesis and mechanical characterization of composite calcite/SWCNT-COOH single crystals. Once entrapped into the crystals SWCNT-COOH appeared both as aggregates of entangled bundles and nanoropes. Their observation was possible only after crystal etching, fracture or FIB (focused ion beam) cross-sectioning. SWCNT-COOHs occupied a small volume fraction and were randomly distributed into the host crystal. They did not strongly affect the crystal morphology. However, although the Young's modulus of composite calcite/SWCNT-COOH single crystals was similar to that of pure calcite their hardness increased by about 20%. Thus, SWCNT-COOHs provide an obstacle against the dislocation-mediated propagation of plastic deformation in the crystalline slip systems, in analogy with the well-known hardness increase in fiber-reinforced composites.
authors.affiliation: Dipartimento di Chimica G. Ciamician, Alma Mater Studiorum Università di Bologna, Via F. Selmi 2, 40126 Bologna, Italy. matteo.calvaresi3@unibo.it
authors.forename: Matteo
authors.initials: M
authors.lastname: Calvaresi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Falini
authors.forename: Luca
authors.initials: L
authors.lastname: Pasquini
authors.forename: Michela
authors.initials: M
authors.lastname: Reggi
authors.forename: Simona
authors.initials: S
authors.lastname: Fermani
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Gazzadi
authors.forename: Stefano
authors.initials: S
authors.lastname: Frabboni
authors.forename: Francesco
authors.initials: F
authors.lastname: Zerbetto