Dual Stimuli-Responsive Smart Fluid of Graphene Oxide-Coated Iron Oxide/Silica Core/Shell Nanoparticles

Abstract

The graphene oxide-coated iron oxide/silica core/shell nanoparticles (Fe3O4/SiO2/GO NPs) are successfully fabricated and adopted as the dual stimuli-responsive smart fluid. The Fe3O4/SiO2/GO NPs exhibit both electrorheological (ER) and magnetorheological (MR) characteristics, attributed to the SiO2/GO layer in the shell part and Fe3O4 in the core part, respectively. Particularly, the ER efficiency of the Fe3O4/SiO2/GO NPs-based ER fluid is ca. 191 at the applied electric field of 3 kV mm–1. Moreover, the MR performance of the Fe3O4/SiO2/GO NPs-based MR fluid is significantly enhanced up to 135-fold at the applied magnetic field of 1 T compared to the zero-field stress. Furthermore, it is remarkable that the Fe3O4/SiO2/GO NPs represent high colloidal stability and outstanding antisettling property because of the electrostatic repulsion between oxygen functional groups on GO nanosheets and the relatively low density compared with other magnetic particles. Dual stimuli-responsive characteristics in addition to the excellent antisedimentation property of the Fe3O4/SiO2/GO NPs-based smart fluid would provide a feasible candidate for practical applications.

Polymer-Magnetic Composite Particles of Fe3O4/Poly(o-anisidine) and Their Suspension Characteristics under Applied Magnetic Fields

“…In the various magnetic field ranges, G′ exhibited a broad plateau area under all different intensity fields and showed an increase in proportion to magnetic intensity. These results reflect the enhanced MR effect of the fluid through higher elasticity and strong MR behavior in the presence of the MR suspension in the presence of the magnetic field [ 31 , 32 ].…”

Magnetic/pH dual‐responsive nanocomposites loading doxorubicin hydrochloride for cancer therapy

“…Stage II is the significant weight loss, which occurs at ∼200–400°C, probably due to the decomposition of organic components, such as citric acid, NH 2 –PEG–NH 2 , hydroxyl, and carboxyl [38, 39]. Stage III, a slower and steady mass loss, which is observed over the whole temperature range between 400 and 600°C, can be assigned to the phase transformation loss of Fe 3 O 4 –Fe 2 O 3 and removal of more stable oxygen functionalities or pyrolysis of the carbon skeleton [40]. A rough calculation manifests that the contents of the citric acid, NH 2 –PEG–NH 2 and GO are about 6.8, 3.1, and 8.2%, respectively.…”

Engineering of a Novel, Magnetic, Bi-Functional, Enzymatic Nanobiocatalyst for the Highly Efficient Synthesis of Enantiopure (R)-3-quinuclidinol

“…For free MLG, no crystalline peaks were found (Figure 4Bc). The diffraction peaks at 2θ = 30.26, 35.48, 43.16, 53.54, 57.12, and 62.74° (in Figure 4Ba,b,d), which corresponded to the lattice spacing of (220), (311), (400), (422),(511), and (440) planes of Fe3O4 crystals [38,39], respectively, matched well with the cubic inverse spinel structure of Fe3O4, suggesting that XRD of the as-synthesized Fe3O4 was in agreement with the pristine Fe3O4 crystal structure data (JCPDS No. 75-0033) [39].…”