[2 + 1] Cycloaddition reactions of fullerene C60 based on diazo compounds

The most common variant of fullerene core functionalization is the [2 + 1] cycloaddition process. Of these, reactions leading to methanofullerenes are the most promising. They are synthesized in two main reactions: nucleophilic cyclopropanation according to the Bingel method and thermal addition of diazo compounds. This present review summarizes the material on the synthesis of monofunctionalized methanofullerenes - analogues of [60]PCBM - based on various diazo compounds. The main cyclopropanating agents for the synthesis of monosubstituted methanofullerenes, the optimal conditions and the mechanism of the [2 + 1] cycloaddition, as well as the practical application of the target products are analyzed.

Aggregation-free and high stability core-shell polymer nanoparticles with high fullerene loading capacity, variable fullerene type, and compatibility towards biological conditions

Fullerenes have unique structural and electronic properties that make them attractive candidates for diagnostic, therapeutic, and theranostic applications. However, their poor water solubility remains a limiting factor in realizing their full biomedical potential. Here, we present an approach based on a combination of supramolecular and covalent chemistry to access well-defined fullerene-containing polymer nanoparticles with a core-shell structure. In this approach, solvophobic forces and aromatic interactions first come into play to afford a micellar structure with a poly(ethylene glycol) shell and a corannulene-based fullerene-rich core. Covalent stabilization of the supramolecular assembly then affords core-crosslinked polymer nanoparticles. The shell makes these nanoparticles biocompatible and allows them to be dried to a solid and redispersed in water without inducing interparticle aggregation. The core allows a high content of different fullerene types to be encapsulated. Finally, covalent stabilization endows nanostructures with stability against changing environmental conditions.

Precise synthesis of double-armed polymers with fullerene C60 at the junction for controlled architecture

We report the first successful synthesis of the polymer-attached 1,2-hydrofullerene and the double-armed 1,4-bisadducts in a regioselective manner via controlled radical reactions.

Polydimethylsiloxane/Nanodiamond Composite Sponge for Enhanced Mechanical or Wettability Performance

Polydimethylsiloxane (PDMS) is widely utilized in material science, chemical engineering, and environmental science due to its excellent properties. By utilizing fillers, so-called composite materials can be obtained with enhanced mechanical, wettability, or thermal conductivity performance. Here, we present a simple, cost-effective approach to vary either the mechanical properties (Young's modulus) or surface wettability of bulk PDMS and PDMS sponges simply by adding nanodiamond filler with different surface terminations, either oxidized (oND) or hydrogenated (reduced, rND) nanodiamond. Minuscule amounts of oxidized nanodiamond particles as filler showed to benefit the compressive Young's modulus of composite sponges with up to a 52% increase in its value, while the wettability of composite sponges was unaffected. In contrast, adding reduced nanodiamond particles to PDMS yielded inclined water contact angles on the PDMS/nanodiamond composite sponges. Finally, we show that the PDMS/rND composites are readily utilized as an absorbent for oil/water separation problems. This signifies that the surface termination of the ND particle has a crucial effect on the performance of the composite.

Striking Effect of Polymer End-Group on C60 Nanoparticle Formation by High Shear Vibrational Milling with Alkyne-Functionalized Poly(2-oxazoline)s

Buckminsterfullerene (C₆₀) has a large potential for biomedical applications. However, the main challenge for the realization of its biomedical application potential is to overcome its extremely low water solubility. One approach is the coformulation with biocompatible water-soluble polymers, such as poly(2-oxazoline)s (PAOx), to form water-soluble C₆₀ nanoparticles (NPs). However, uniform and defined NPs have only been obtained via a thin film hydration method or using cyclodextrin-functionalized PAOx. Here, we report the mechanochemical preparation of defined and stable C₆₀:PAOx NPs by the introduction of a simple alkyne group as a polymer end-group. The presence of this alkyne bond is proven to be crucial in the mechanochemical synthesis of stable, defined sub-100 nm C₆₀:PAOx NPs, with high C₆₀ content up to 8.9 wt %.

Switching Brake Materials To Extremely Wear-Resistant Self-Lubrication Materials via Tuning Interface Nanostructures

Tribological performance of motion components is one of the key aspects that must be considered in a wide range of applications such as vehicles, aircrafts, and manufacturing equipment. This work demonstrates that further addition of only low-loading hard nanoparticles into a formulated nonasbestos organic brake material directly switches its functionality to a self-lubrication material. More importantly, the newly developed nanocomposites exhibit an extremely low wear rate. Comprehensive investigations on the friction interface reveal that the great friction and wear reduction are due to the formation of a nanostructured lubricious tribofilm. Tribofilm formation is continuously fed by complex molecular species released from the bulk nanocomposites, for which nanoparticles digested within the tribofilm greatly enhance its robustness and lubricity. This work gains insight into the crucial role of the interface nanostructure and paves a route for developing extremely wear-resistant self-lubrication composites for numerous applications.

Electronic compensation-induced stabilization of carbon dots@PMMA under UV aging

As-prepared FOCDs could enhance the stability of optical polymers under UV aging through timely electron compensation with no deterioration in transparency.

Synthesis, characterization, optical and antimicrobial studies of polyvinyl alcohol-silver nanocomposites

Silver nanoparticles (Ag NPs) were synthesized by chemical reduction of silver salt (AgNO3) through sodium borohydride. The characteristic surface plasmon resonance band located at around 400nm in the UV-Visible absorption spectrum confirmed the formation of Ag nanoparticles. Polyvinyl alcohol-silver (PVA-Ag) nanocomposite films were prepared by the casting technique. The morphology and interaction of PVA with Ag NPs were examined by transmission electron microscopy and FTIR spectroscopy. Optical studies show that PVA exhibited indirect allowed optical transition with optical energy gap of 4.8eV, which reduced to 4.45eV under addition of Ag NPs. Optical parameters such as refractive index, complex dielectric constant and their dispersions have been analyzed using Wemple and DiDomenco model. Color properties of the nanocomposites are discussed in the framework of CIE L(∗)u(∗)v(∗) color space. The antimicrobial activity of the nanocomposite samples was tested against Gram positive bacteria (Staphylococcus aureus NCTC 7447 &Bacillus subtillis NCIB 3610), Gram negative bacteria (Escherichia coli, NTC10416 &Pseudomonas aeruginosa NCIB 9016) and fungi (Aspergillus niger Ferm - BAM C-21) using the agar diffusion technique. The antimicrobial study showed that PVA has moderate antibacterial activity against B. subtillis and the 0.04wt% Ag NPs composite sample effect was strong against S. aureus.

Facile fabrication of polycaprolactone/h-MoO3 nanocomposites and their structural, optical and electrical properties

Hexagonal molybdenum oxide (h-MoO₃) nanocrystals with a flower-like hierarchical structure were successfully incorporated into polycaprolactone (PCL) matrix by a simple solution casting technique.

Facile construction of well-defined fullerene–dendrimer supramolecular nanocomposites for bioapplications

Well-defined supramolecular nanocomposites with biofunctions were facilely fabricated through complexation of carboxyfullerenes with poly(ethylene glycol)-modified poly(amidoamine) dendrimers.

The effect of amphiphilic polymers on the association, morphology and photophysical properties of hypocrellin coordination polymer/fullerene assemblies

Y³⁺–PyrHA/fullerene can form nanoparticles in the size range of 10–60 nm and exhibits a higher singlet oxygen quantum yield than Y³⁺–PyrHA and the corresponding fullerene in 1% P123 solution.

Properties of Natural Rubber-Based Composites Containing Fullerene

In this study the influence of fullerenes in concentrations from 0.5 to 1.5 phr on both the vulcanization characteristics of the compounds and physicomechanical, dynamic, and dielectric properties and thermal aging resistance of nanocomposites on the basis of natural rubber has been investigated. The effect of the filler dispersion in the elastomeric matrix has been also investigated. Neat fullerene and the composites comprising it have been studied and characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).