Construction of a Self-Assembled Polyelectrolyte/Graphene Oxide Multilayer Film and Its Interaction with Metal Ions

Abstract

In this study, a composite multilayer film onto gold was constructed from two charged building blocks, i.e., negatively charged graphene oxide (GO) and a branched polycation (polyethylenimine, PEI) via layer-by-layer (LbL) self-assembly technology, and this process was monitored in situ with quartz crystal microbalance (QCM) under different experimental conditions. This included the differences in frequency (Δf) as well as the changes in dissipation to yield information on the absorbed mass and viscoelastic properties of the formed PEI/GO multilayer films. The experimental conditions were optimized to obtain a high amount of the adsorbed mass of the self-assembled multilayer film. The surface morphology of the PEI/GO multilayer film onto gold was studied with atomic force microscopy (AFM). It was found that the positively charged PEI chains were combined with the oppositely charged GO to form an assembled film on the QCM sensor surface, in a wrapped and curled fashion. Raman and UV-vis spectra also showed that the intensities of the GO-characteristic signals are almost linearly related to the layer number. To explore the films for their use in divalent ion detection, the frequency response of the PEI/GO multilayer-modified QCM sensor to the exposure of aqueous solutions solution of Cu2+, Ca2+, Zn2+, and Sn2+ was further studied using QCM. Based on the Sauerbrey equation and the weight of different ions, the number of metal ions adsorbed per unit area on the surface of QCM sensors was calculated. For metal ion concentrations of 40 ppm, the adsorption capacities per unit area of Cu2+, Zn2+, Sn2+, and Ca2+ were found to be 1.7, 3.2, 0.7, and 4.9 nmol/cm2, respectively. Thus, in terms of the number of adsorbed ions per unit area, the QCM sensor modified by PEI/GO multilayer film shows the largest adsorption capacity of Ca2+. This can be rationalized by the relative hydration energies.

Binder-Free Freestanding 3D Zn-Graphene Anode Induced from Commercial Zinc Powders and Graphene Oxide for Zinc Ion Battery with High Utilization Rate

“…In addition to the Pi-Pi stacking between the rGO sheets, the interaction between zinc ions and the residual functional groups on rGO sheets enhance the cross-link and form an integral freestanding electrode. 39 The process of Zn_G fabrication is illustrated in Figure 1a Zn powders and GO dispersion were mixed well in an ice bath.…”

“…In this work, the composition of Zn powders and reduced graphene (rGO) sheets were chemically combined without extra binders, which were labeled as Zn_G. In addition to the Pi-Pi stacking between the rGO sheets, the interaction between zinc ions and the residual functional groups on rGO sheets enhance the cross-link and form an integral freestanding electrode . The process of Zn_G fabrication is illustrated in Figure a.…”

Probing the Interaction of Heavy and Transition Metal Ions with Silver Nanoparticles Decorated on Graphene Quantum Dots by Spectroscopic and Microscopic Methods

“…The presence of a graphene surface on GQDs opened the possibility of the strong adsorption of these metal ions. The stable anchoring of metals and metal ions on graphene compounds has been reported previously. , The adsorptive interaction of metal ions with functionalized graphene such as graphene oxide and their polymer composites has been well established. − Shtepliuk and co-workers studied the interaction of heavy metal ions with GQDs and suggested the possible adsorption sites for heavy metals and their monovalent and bivalent cations. The possible adsorption sites are schematically illustrated in Figure .…”

Applications of Graphene in Five Senses, Nervous System, and Artificial Muscles

“…First, the transistor applications with graphene channels preferred the wafer-scale growth of monolayer graphene , (directly grown) on Si related dielectric substrates , or meter-scale chemical vapor deposition growth over metal substrates . Second, the graphene nanosheets , are incorporated into supramolecular nanostructures and composites, − deposited for thin films, , and assembled into macroforms such as aerogel − or hydrogel . The lateral size and vertical thickness of graphene nanosheets require homogeneity for controllable conductivity and device performance.…”