Latex routes to graphene-based nanocomposites

Abstract

International audienceThis review article describes recent advances in the elaboration of graphene-based colloidal nanocomposites by the use of graphene or graphene oxide in heterophase polymerization systems. Two main routes are reviewed: latex blending and in situ polymerization. In the first strategy, a segregated network is formed by confining the graphenic fillers in the interstices between the latex particles during the drying process. The morphology of the network depends on the relative dimensions of the fillers and the latex particles and on the interfacial interactions. The various approaches used to promote latex/graphene interactions via charge attractions or pi stacking are reviewed. The second method relies on the in situ formation of polymer latexes in the presence of graphenic fillers using emulsion, miniemulsion or suspension polymerization processes in the presence or absence of a stabilizer. The use of graphene oxide as a Pickering stabilizer and the effect of the dimensional characteristics of the graphene sheets on particle morphology are also discussed. Finally, a brief discussion of the mechanical and electrical properties of graphene-latex nanocomposites with regard to the characteristics of the filler and the latex-graphene relative dimensions is given to provide insight into the main requirements of graphenic fillers with respects to various applications

Formation of homogeneous nanocomposite films at ambient temperature via miniemulsion polymerization using graphene oxide as surfactant

“…Solution blending, which entails swelling of graphene/polymer with a suitable solvent, is associated with the issue of subsequent solvent removal . Physical mixing methods, which typically involve blending a polymer latex with graphene, may result in a so called cellular morphology (graphene walls and polymer cells)—however, it can be a significant challenge to retain such a morphology in the final nanocomposite . Moreover, blending techniques usually have issues with aggregation of GO sheets within the composite structure, leading to a heterogeneous filler distribution .…”

“…It was recently reported that GO has amphiphilic properties and can act as surfactant in oil‐in‐water emulsions . The amphiphilic properties of GO enable it to remain at the interface between the aqueous and oil phase (solid/liquid or liquid/liquid) allowing stabilization of monomer droplets in an aqueous emulsion . Miniemulsion polymerization of GO‐based Pickering emulsions provides an attractive route to polymer nanoparticles armored with GO sheets .…”

Mechanochemical Routes to Functionalized Graphene Nanofillers Tuned for Lightweight Carbon/Hydrocarbon Composites

“…The presence of functional groups enables electrostatic stabilization of functionalized graphene dispersions in water and various organic media without addition of surfactants and other dispersing aids . Furthermore, aqueous graphene oxide and graphite oxide dispersions represent attractive intermediates for polymer nanocomposite formation via dispersion blending with polymer latex and by polymerization filling . However, the synthesis of high‐purity graphite oxide requires tedious purification and special safety and handling precautions taking into account its explosive nature …”

“…[88,89] Furthermore, aqueous graphene oxide and graphite oxide dispersions represent attractive intermediates for polymer nanocomposite formation via dispersion blending with polymer latex and by polymerization filling. [90] However, the synthesis of high-purity graphite oxide requires tedious purification and special safety and handling precautions taking into account its explosive nature. [91] Opposite to wet-chemistry processes which require extensive and expensive additional purification steps for solvent recovery and by-product removal, solvent-free mechanochemistry processes hold great promise regarding the environmentally friendly and sustainable syntheses of nanoparticles tailored for a variety of applications ranging from catalysis to electronics, advanced optics, and nanocomposites.…”

Self‐assembly of block copolymers with an alkoxysilane‐based core‐forming block: A comparison of synthetic approaches

“…These hybrid materials are typically pursued for their attractive properties; some examples include the enhancement of mechanical strength of a matrix relative to the neat polymer, response to an applied magnetic field, incorporation of nanomaterials with catalytic function as well as optical properties for diagnostic imaging . The range of materials used to prepare such nanocomposites is extensive, with published examples including natural and synthetic clays, (semi‐)metal oxide nanoparticles, graphene‐derived nanosheets, carbon nanotubes, layered double hydroxides, and quantum dots . Aside from the layer‐by‐layer deposition approach, the most common method of creating such composite materials is heterophase polymerization, which encompasses emulsion, miniemulsion and dispersion polymerization .…”