The graphene nanosheets-based epoxy resin coating (0, 0.1, 0.4 and 0.7 wt %) was prepared by a situ-synthesis method. The effect of polyvinylpyrrolidone/reduced graphene oxide (PVP-rGO) on mechanical and thermal properties of epoxy resin coating was investigated using nanoindentation technique and thermogravimetric analysis, respectively. A significant enhancement (ca. 213% and 73 °C) in the Young modulus and thermal stability of epoxy resin coating was obtained at a loading of 0.7 wt %, respectively. Furthermore, the erosion resistance of graphene nanosheets-based epoxy resin coating was investigated by electrochemical measurement. The results showed also that the Rrcco (ca. 0.3 mm/year) of graphene nanosheets-based epoxy resin coating was far lower than neat epoxy resin (1.3 mm/year). Thus, this approach provides a novel route for improving erosion resistance and mechanical-thermal stability of polymers coating, which is expected to be used in mechanical-thermal-corrosion coupling environments.

Silver nanoparticles grown on reduced graphene oxide (AgNPs/RGO) were successfully synthesized via a facile in situ method. The samples were characterized by scanning electron microscopy (SEM), Raman spectroscopy, field emission transmission electron microscopy (FETEM) and X-ray diffraction (XRD). The results show that silver ions distribute extensively on the RGO sheets. In order to prepare an electrochemical sensor, the AgNPs/RGO nanocomposite was used to modify the surface of a magnetic glassy carbon electrode. The device was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The as-prepared AgNPs/RGO nanocomposite was measured with square wave anodic stripping voltammetry (SWASV), and exhibited excellent electrochemical activity and sensitivity towards the detection of heavy metal ions, including Pb(II), Cd(II), Cu(II) and Hg(II). The sensitivities were respectively 48.69, 40.06, 15.66 and 43.18 μA μM⁻¹ and the limits of detection (LOD) were respectively 0.141, 0.254, 0.178 and 0.285 μM. Compared to the bare RGO film, the AgNPs/RGO nanocomposite showed a significantly higher activity for anodic stripping analysis of the four considered heavy metal ions; in particular, the peak current enhancement was about 1.5 times higher for Pb(II). Experiments also show that the AgNPs/RGO-modified electrode displays good anti-interference properties. Moreover, this study provides a potential material for electrochemical detection of heavy metal ions, individually or simultaneously.

Graphene-based polymer composite films have wide-ranging potential applications, such as in sensors, electromagnetic shielding, absorbing materials, corrosion resistance and so on. In addition, the practical applications of graphene-based polymer composite films are closely related to their mechanical properties. However, the mechanical properties of graphene-based polymer composite films are difficult to characterize with tensile tests. In this paper, the bugle test was used to investigate the mechanical properties of graphene-based polymer composite films. The experimental results show that the Young’s modulus of polymer composite films increases non-linearly with an increase in the doping content of graphene, and viscoelastic deformation is induced under cyclic loading conditions. Moreover, in order to describe their mechanical behavior, an ‘Arruda–Boyce’ finite-strain constitutive model (modified BPA model), based on the strain amplification hypothesis, and a traditional ‘Arruda–Boyce’ model was proposed, which incorporated many of the features of previous theories. The numerical treatment of the modified BPA model associated with finite element analysis is also discussed. This new model is shown to be able to predict the experimentally observed mechanical behavior of graphene based polymer composite films measured by the bugle test effectively.

This paper presents a new flexible magnetic field sensor based on Ag nanowires and magnetic nanoparticles doped in polydimethylsiloxane (AgNWs & MNs-PDMS) with sandwich structure. The MNs act as the sensitive unit for magnetic field sensing in this work. Besides, the conductive networks are made by AgNWs during deformation. Magnetostriction leads to the resistance change of the AgNWs & MNs-PDMS sensors. Furthermore, the MNs increase the conductive paths for electrons, leading to lower initial resistance and higher sensitivity of the resulting sensor during deformation. A point worth emphasizing is that the interaction of the AgNWs and MNs plays irreplaceable role in magnetic field sensing, so the resistance change during stretching and shrinking was investigated. The flexible magnetic field sensor based on the mass ratio of MNs and AgNWs is 1:5 showed the highest sensitivity of 24.14 Ω/T in magnetic field sensing experiment. Finally, the magnetostrictive and piezoresistive sensing model were established to explore the mechanism of the sensor.