Treelike Polymeric Ionic Liquids Grafted onto Graphene Nanosheets

Ion channels in sulfonated copolymer-grafted nanoparticles in ionic liquids

The use of ionic liquids as solvents for polymers or polymer-grafted nanoparticles provides an exciting feature to explore electrolyte-polymer interactions. 1-Hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIm-TFSI) can have specific interactions with the polymer through ion-dipole forces or hydrogen bonding. In this work, poly(methyl methacrylate)-b-poly(styrene sulfonate) (PMMA-b-PSS) copolymer-grafted Fe₃O₄ nanoparticles with different sulfonation levels (∼4.9 to 10.9 mol% SS) were synthesized, and their concentration dependent ionic conductivities were reported in acetonitrile and HMIm-TFSI/acetonitrile mixtures. We found that conductivity enhancement with the particle concentration in acetonitrile was due to the aggregation of grafted particles, resulting in sulfonic domain connectivity. The ionic conductivity was found to be related to the effective hopping transfer within ionic channels. On the contrary, the conductivity decreased or remained constant with increasing particle concentration in HMIm-TFSI/acetonitrile. This result was attributed to the ion coupling between ionic liquids and copolymer domains.

Copper(ii) ions supported on functionalized graphene oxide: an organometallic nanocatalyst for oxidative amination of azoles via C–H/C–N bond activation

Graphene oxide (GO) was chemically modified with para-aminobenzoic acid (PABA) to immobilize copper(ii) ions on its surface and used as a nanocatalyst for the oxidative C (sp²)–H bond amination reaction.

Linear and Star Poly(ionic liquid) Assemblies: Surface Monolayers and Multilayers

The surface morphology and organization of poly(ionic liquid)s (PILs), poly[1-(4-vinylbenzyl)-3-butylimidazolium bis(trifluoromethylsulfonyl)imide] are explored in conjunction with their molecular architecture, adsorption conditions, and postassembly treatments. The formation of stable PIL Langmuir and Langmuir-Blodgett (LB) monolayers at the air-water and air-solid interfaces is demonstrated. The hydrophobic bis(trifluoromethylsulfonyl)imide (Tf₂N^-) is shown to be a critical agent governing the assembly morphology, as observed in the reversible condensation of LB monolayers into dense nanodroplets. The PIL is then incorporated as an unconventional polyelectrolyte component in the layer-by-layer (LbL) films of hydrophobic character. We demonstrate that the interplay of capillary forces, macromolecular mobility, and structural relaxation of the polymer chains influence the dewetting mechanisms in the PIL multilayers, thereby enabling access to a diverse set of highly textured, porous, and interconnected network morphologies for PIL LbL films that would otherwise be absent in conventional LbL films. Their compartmentalized internal structure is relevant to molecular separation membranes, ultrathin hydrophobic coatings, targeted cargo delivery, and highly conductive films.

Treelike polymeric phosphate esters grafted onto graphene oxide and its tribological properties in polyalkylene glycol for steel/steel contact at elevated temperature

We report the first synthesis of a high-performance lubricant additive by grafting treelike polymeric phosphate esters (PPEs) onto graphene oxide (GO) nanosheets.

AuCu and AgCu bimetallic nanoparticles supported on guanidine-modified reduced graphene oxide nanosheets as catalysts in the reduction of nitroarenes: tandem synthesis of benzo[b][1,4]diazepine derivatives

AuCu and AgCu bimetallic nanoparticles supported on guanidine-grafted reduced graphene oxide nanosheets as reduction catalysts.

Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s

Branched polyelectrolytes with cylindrical brush, dendritic, hyperbranched, grafted, and star architectures bearing ionizable functional groups possess complex and unique assembly behavior in solution at surfaces and interfaces as compared to their linear counterparts. This review summarizes the recent developments in the introduction of various architectures and understanding of the assembly behavior of branched polyelectrolytes with a focus on functional polyelectrolytes and poly(ionic liquid)s with responsive properties. The branched polyelectrolytes and poly(ionic liquid)s interact electrostatically with small molecules, linear polyelectrolytes, or other branched polyelectrolytes to form assemblies of hybrid nanoparticles, multilayer thin films, responsive microcapsules, and ion-conductive membranes. The branched structures lead to unconventional assemblies and complex hierarchical structures with responsive properties as summarized in this review. Finally, we discuss prospectives for emerging applications of branched polyelectrolytes and poly(ionic liquid)s for energy harvesting and storage, controlled delivery, chemical microreactors, adaptive surfaces, and ion-exchange membranes.

Synthesis of copper graphene materials functionalized by amino acids and their catalytic applications

Graphene oxide and its derivative have attracted extensive interests in many fields, including catalytic chemistry, organic synthesis, and electrochemistry, recently. We explored whether the use of graphene after chemical modification with amino acids to immobilize copper nanoparticles could achieve a more excellent catalytic activity for N-arylation reactions. A facile and novel method to prepare copper supported on amino-acid-grafted graphene hybrid materials (A-G-Cu) was first reported. The as-prepared hybrid materials were characterized by a variety of techniques, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and inductively coupled plasma-atomic emission spectrometry. The results showed that the morphology, distribution, and loading of copper nanoparticles could be well-adjusted by controlling the type of amino acids grafted on graphene. Moreover, most A-G-Cu hybrid materials could catalyze N-arylation of imidazole with iodobenzene with yields more than 90%, while the copper supported on graphene (G-Cu) displayed a yield of just 65.8%. The high activity of A-G-Cu can be ascribed to the good synergistic effects of copper nanoparticles (Cu NPs) and amino-acid-grafted graphene.