Composites of Graphene and Other Nanocarbons with Organogelators Assembled through Supramolecular Interactions

Abstract

Carbon nanomaterials (CNMs), such as exfoliated graphene (EG), long-chain functionalized EG, single-walled carbon nanotubes (SWNTs), and fullerene (C(60)), have been investigated for their interaction with two structurally different gelators based on all-trans tri-p-phenylenevinylene bis-aldoxime (1) and n-lauroyl-L-alanine (2) both in solution and in supramolecular organogels. Gelation occurs in toluene through hydrogen bonding and van der Waals interactions for 1 and 2 in addition to π-π stacking specifically in the case of 1. These nanocomposites provide a thorough understanding in terms of molecular-level interactions of dimensionally different CNMs with structurally different gelators. The presence of densely wrapped CNMs encapsulated fibrous network in the resulting composites is evident from various spectroscopic and microscopic studies, indicating the presence of supramolecular interactions. Concentration- and temperature-dependent UV/Vis and fluorescence spectra show that CNMs promote aggregation of the gelator molecules, leading to hypochromism and quenching of the fluorescence intensity. Thermotropic mesophases of 1 are altered by the inclusion of a small amount of CNMs. The gel-CNM composites show increased electrical conductivity compared with that of the native organogel. Rheological studies of the composites demonstrate the formation of rigid and viscoelastic solidlike assembly due to reinforced aggregation of the gelators on CNMs. Synergistic behavior is observed in case of the composite gel of 1, containing a mixture of EG and SWNT, when compared with other mixtures of CNMs in all combinations with EG. This affords new nanocomposites with interesting optical, thermal, electrical, and mechanical properties.

Preparation and interaction study between fullerene and graphene in a polymeric matrix

“…However, a quenching effect that is similar to that observed in our samples was also reported in some composites of graphene with fluorescent organogelators. A decrease in the emission intensity of the composite was seen at higher graphene contents, modified by the presence of fullerene C60, which acted also as strong quencher preventing the aggregation [58]. On the other hand, there is no evidence of emission in samples containing only fullerene C60 at different amounts.…”

Efficient Management of Fruit Pests by Pheromone Nanogels

“…Low-molecular mass gelators (LMMGs) have attracted much attention because of their interesting properties and potential uses in various fields of research and industry3334. LMMGs such as all- trans tri( p -phenylenevinylene) bis-aldoxime ( 1 )35, self-assemble through weak intermolecular non-covalent interactions such as hydrogen bonding, π-π stacking and van der Waals leading to the gelation of specific solvents (Figure 2)36373839. In the present work, we demonstrate the nanogel formation upon entrapment and immobilization of ME into the entangled three-dimensional nano-sized supramolecular networks of 1 .…”

6. Graphene and its hybrids with inorganic nanoparticles, polymers and other materials

“…The two main approaches for obtaining this type of graphene are covalent functionalization or by means of noncovalent interactions. There has been some recent effort to carry out covalent and noncovalent functionalization of graphene with aromatic molecules, which help to exfoliate and stabilize the individual graphene sheets and to modify their electronic properties [75][76][77][78][79][80][81][82][83][84].…”

“…Noncovalent functionalization and solubilization of graphene in water is achieved by employing CS to yield monolayer graphene-CS hybrids (see Fig. 6.8) [75][76][77][78][79][80][81][82][83][84]. Recently, interaction of electron-donor and -acceptor molecules with graphenes has been exploited to modify the electronic properties of graphene through ground-state charge transfer [91][92][93][94][95].…”