Role of Aryl Amphiphile Hydrophobe Size on the Concentration and Stability of Graphene Nanoplatelet Dispersions.

Graphene nanoplatelets (GNPs) are stable and relatively inexpensive compared to single-layer graphene sheets and carbon nanotubes and are useful in diverse electronic, optoelectronic, and mechanical applications. Solution-state processing of the active material is desired in most of the applications mentioned above, and thus, there is great interest in increasing the concentration and stability of GNP suspension. Herein, to elucidate the role of the stabilizer structural parameters on the concentration and stability of GNP dispersions, we synthesized and used a series of aryl amphiphiles (ArAs) of varying aryl hydrophobe sizes and geometries. The ArAs were found to generate GNP dispersions with concentrations ranging from 0.05 to 0.13 mg mL-1 depending on the size of the aryl hydrophobe. The ArAs' hydrophobe size played a key role in determining the concentration of GNP suspension, while ArAs' critical aggregation concentration and solubility limits had no impact on the GNP suspension concentration. Most of the studied ArAs work similar to methylcellulose, the previously reported best performing stabilizer . Moreover, the ArAs stabilized the GNP suspension better than methylcellulose and were able to form stable dispersions for up to 6 h. Raman studies indicate that the quality of the GNPs did not degrade during the dispersion process. These findings will aid in the development of design rules for next-generation stabilizers.

Waveguiding properties of perylene microcrystals synthesized by retarding the growth along the π-stack direction.

Selective, hard to realize growth retardation of the π-stacking direction over the edge-packing direction has been achieved in perylene microcrystals using an aryl amphiphile. The perylene microcrystals grow predominantly along the edge-packing direction resulting in novel and hitherto unknown perylene square rods. The rods show exciton-polariton waveguiding along the rod axis even though it corresponds to pure edge-packing of the molecules, which is unprecedented in organic microcrystals.

Aryl amphiphile shape-directors for shape-controlled synthesis of organic semiconductor particles.

Currently, shape- and size-controlled synthesis of organic micro- and nano-particles mostly relies on aliphatic amphiphiles, which lack the structural diversity to provide tunable amphiphile-particle facet interaction energies and result in a limited range of particle shapes. Herein we report the design, synthesis, and utilization of two novel aryl amphiphiles as shape-directors (ShaDs) to obtain particles of different shape. By changing the ShaDs aryl hydrophobe structure, 9,10-diphenylanthracene microcrystals of different shape were obtained with greater than 90% shape yield.