Elastic flexibility tuning via interaction factor modulation in molecular crystals.

We report the design of a series of nonhalogenated and halogenated molecular crystals with specific structural features, which are essential for pronounced elasticity. These features involve (a) isotropic weak and dispersive interactions, and (b) corrugated molecular packing with interlocked structures. The effects of intermolecular interactions on the elastic properties of the crystals are ascertained using nano-scale mechanical characterization methods.

Carbon-Nanohorn-Reinforced Polymer Matrix Composites: Synergetic Benefits in Mechanical Properties.

Mechanical properties of single-walled carbon nanohorns (SWNH) and SWNH plus few-layer graphene (EG)-reinforced poly(vinyl alcohol) (PVA) matrix composites have been measured using the nanoindentation technique. The elastic modulus (E) and hardness (H) of PVA were found to improve by ∼315% and ∼135%, respectively, upon the addition of just 0.4 wt % SWNH.

Designing elastic organic crystals: highly flexible polyhalogenated N-benzylideneanilines.

The intermolecular interactions and structural features in crystals of seven halogenated N-benzylideneanilines (Schiff bases), all of which exhibit remarkable flexibility, were examined to identify the common packing features that are the raison d'être for the observed elasticity. The following two features, in part related, were identified as essential to obtain elastic organic crystals: 1) A multitude of weak and dispersive interactions, including halogen bonds, which may act as structural buffers for deformation through easy rupture and reformation during bending; and 2) corrugated packing patterns that would get interlocked and, in the process, prevent long-range sliding of molecular planes.