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In this study, we used direct molecular exfoliation for the rapid, facile, large-scale fabrication of single-layered graphene oxide nanosheets (GOSs). Using macromolecular polyaniline (PANI) as a layered space enlarger, we readily and rapidly synthesized individual GOSs at room temperature through the in situ polymerization of aniline on the 2D GOS platform. The chemically modified GOS platelets formed unique 2D-layered GOS/PANI hybrids, with the PANI nanorods embedded between the GO interlayers and extended over the GO surface. X-ray diffraction revealed that intergallery expansion occurred in the GO basal spacing after the PANI nanorods had anchored and grown onto the surface of the GO layer. Transparent folding GOSs were, therefore, observed in transmission electron microscopy images. GOS/PANI nanohybrids possessing high conductivities and large work functions have the potential for application as electrode materials in optoelectronic devices. Our dispersion/exfoliation methodology is a facile means of preparing individual GOS platelets with high throughput, potentially expanding the applicability of nanographene oxide materials.

In this study, we synthesized a series of amphiphilic dumbbell-shaped dendrimers through the addition reactions of a hydrophilic poly(oxyalkylene) with hydrophobic dendrons based on 4-isocyanate-4'-(3,3-dimethyl-2,4-dioxo-azetidine)diphenylmethane with different numbers of branching generations. The addition reaction of azetidine-2,4-diones of dendrons to amines of poly(oxyalkylene) was proceeded by stirring the reactants in dry tetrahydrofuran (THF) under nitrogen at 60 °C. In aqueous media, the dumbbell-shaped dendrimers self-assembled into micelles with their hydrophobic dendrons in the core and their hydrophilic poly(oxyalkylene) segments forming loops in the corona shell. Employing the unique self-assembled micelle structures as templates for subsequent chemical reduction of the Ag(+) ions, we generated new types of organic/metallic [silver nanoparticle (AgNP)] nanohybrid clusters. The long poly(oxyalkylene) loops that extended into the aqueous phase complexed with the Ag(+) ions, providing the suspension with steric stabilization to prevent the AgNPs from collision and flocculation. After reduction, the AgNPs were present in a homogeneous distribution in the round dendrimer micelle-stabilized nanoclusters. The diameter of each AgNP was less than 10 nm; the diameter of each round nanocluster was in the range of 50-200 nm. The encapsulation efficiency of the AgNPs in micelles was about 54-69% for the dumbbell-shaped dendrimer based organic/AgNP nanohybrid.

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In this study, we used a solution process, involving direct molecular exfoliation of graphite oxide (GO) stacked layers, to obtain individual graphene oxide platelets (GOPs) through amphiphilic hyperbranched polymers (HPs). The HPs, based on poly(amic acid) and polyimide with terminal amino functionalities, were obtained through a facile "A(2) + B-3'' synthesis; gel permeation chromatography of the HPs revealed molecular weights of 5000-8200 g mol(-1) with a distribution of polydispersity between 2.0 and 4.2. Next, we inserted these globular HPs into the interlayer spaces of GO to prepare a series of GO/HP nanohybrids possessing intercalated and exfoliated morphologies. The intercalation processes featured a critical transition point at which a dramatic enlargement occurred to the interlayer spacing, depending on the content of the bulky embedded HPs. From transmission electron microscopy images, we observed transparent folding of the GOPs; powder X-ray diffraction analysis revealed individual nanosheets with well-defined diffraction patterns. Incorporating the bulky three-dimensional globular structure into the layered GO significantly influenced the solution exfoliation, allowing us to examine the intercalating behavior of GO intergallery. This solution-phase methodology, through direct HP molecular exfoliation, provides the way toward obtaining individual nanosheets, opening up opportunities for platelet-like nanographene oxide materials in many technological applications