Conducting and Magnetic Composites Polypyrrole Nanotubes/Magnetite Nanoparticles: Application in Magnetorheology

Stejskal, Jaroslav; Sapurina, Irina; Vilčáková, Jarmila; Plachý, Tomáš; Sedlačík, Michal; Bubulinca, Constantin; Gořalík, Marek; Kolská, Zdeňka; Prokeš, Ján

doi:10.1021/acsanm.1c00063

Cited by 15 publications

(9 citation statements)

References 55 publications

(104 reference statements)

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“…Despite the importance of surface properties, SSA values for constituents of magnetic fluids have rarely been published. As seen in Table 1 , the SSA of magnetic nano-fillers [ 30 , 36 , 37 , 38 ] usually ranges between 40 and 190 m 2 /g, whereas for non-magnetic nano-fillers such as silica [ 32 ], it attains values of approximately 115–200 m 2 /g. These values were exceeded by the NPs@m-TEOS particles (312 m 2 /g), revealing that the biphase stratification method had the potential to facilitate formation of an active interface that could be penetrated by a carrier liquid.…”

Section: Resultsmentioning

confidence: 99%

Stable Magnetorheological Fluids Containing Bidisperse Fillers with Compact/Mesoporous Silica Coatings

Cvek

Jamatia

Šuly

et al. 2022

IJMS

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A drawback of magnetorheological fluids is low kinetic stability, which severely limits their practical utilization. This paper describes the suppression of sedimentation through a combination of bidispersal and coating techniques. A magnetic, sub-micro additive was fabricated and sequentially coated with organosilanes. The first layer was represented by compact silica, while the outer layer consisted of mesoporous silica, obtained with the oil–water biphase stratification method. The success of the modification technique was evidenced with transmission electron microscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The coating exceptionally increased the specific surface area, from 47 m2/g (neat particles) up to 312 m2/g, which when combined with lower density, resulted in remarkable improvement in the sedimentation profile. At this expense, the compact/mesoporous silica slightly diminished the magnetization of the particles, while the magnetorheological performance remained at an acceptable level, as evaluated with a modified version of the Cross model. Sedimentation curves were, for the first time in magnetorheology, modelled via a novel five-parameter equation (S-model) that showed a robust fitting capability. The sub-micro additive prevented the primary carbonyl iron particles from aggregation, which was projected into the improved sedimentation behavior (up to a six-fold reduction in the sedimentation rate). Detailed focus was also given to analyze the implications of the sub-micro additives and their surface texture on the overall behavior of the bidisperse magnetorheological fluids.

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Section: Resultsmentioning

confidence: 99%

Stable Magnetorheological Fluids Containing Bidisperse Fillers with Compact/Mesoporous Silica Coatings

Cvek

Jamatia

Šuly

et al. 2022

IJMS

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“…At a 250 kA m −1 magnetic field, the τ sy of FeCoNP-MRFs is reached to be approximately 4.83 kPa. The yield stress difference value between τ sy and τ dy is not very large, indicating the appearance of the strong magnetic interaction force between the FeCo nanoparticles [37].…”

Section: The Mr Properties and Practicability Of Feconp-mrfsmentioning

confidence: 93%

Magnetorheological properties of Fe–Co nanoparticles with high saturation magnetization and low coercivity

Du¹,

Zhao²,

Tong³

et al. 2023

Nanotechnology

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Fe-Co alloys exhibit an excellent saturation magnetization, which makes them become a potential candidate for the high property magnetic particles in magnetorheological fluids (MRFs). How to decrease their coercivity and residual magnetization without sacrificing the saturation magnetization is a crucial problem to be solved. In this study, Fe-Co nanoparticles were prepared by DC arc discharge and further disposed through low temperature annealing in Ar atmosphere. The successful synthesis of Fe-Co nanoparticles was proved by XRD and EDS. The VSM results revealed that the prepared Fe-Co nanoparticles had a saturation magnetization of 208 emu/g, while the coercivity and remanent magnetization were 58 Oe and 5.8 emu/g, respectively. The MR properties of Fe-Co nanoparticles based MRFs (FeCoNP-MRFs) with 10% particles by volume fraction were systematically investigated. The FeCoNP-MRFs showed up to 4.61 kPa dynamic shear stress at 436 kA/m magnetic field and an excellent reversibility. The MR properties of FeCoNP-MRFs were fitted well by Bingham and power law model, and described by Seo-Seo and Casson fluid model. Meanwhile, the sedimentation ratio of FeCoNP-MRFs was still 87.3% after 72 hours, indicating an excellent sedimentation stability.

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“…To reveal this answer, polypyrrole nanotubes (PNTs) have been selected as precursors due to their several advantages, such as one-dimensional structure, aromatic conjugated polymer molecules, good porosity, abundant nitrogen atoms, and anchoring the inorganic nanoparticles. , Moreover, PNT-derived carbon can reduce the ZnO and the doping nitrogen atoms can stabilize the Zn single atoms. Three-dimensional graphene aerogels have been regarded as one of the desirable candidates for supporting electrocatalysts, since they show excellent conductivity, large specific surface areas, and high mass efficiency.…”

Section: Introductionmentioning

confidence: 99%

Zn Single Atoms/Clusters/Nanoparticles Embedded in the Hybrid Carbon Aerogels for High-Performance ORR Electrocatalysis

Wei,

Chen,

Tian

et al. 2023

Inorg. Chem.

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Carbon-supported zinc single-atom catalysts have received considerable attention in the electrocatalytic oxygen reduction reaction (ORR) owing to the strong reduction capacity of zinc atoms and the abundant reserves of zinc elements. The common preparation method has been limited to the high-temperature pyrolysis of nitrogen-rich organic molecules and zinc ions, which makes it difficult to further improve the ORR performance. Herein, we first prepared ZnO/PNT/rGO aerogels as precursors via a simple hydrothermal method combined with freeze-drying, in which reduced graphene oxides (rGO) and polypyrrole nanotubes (PNT) together assembled into three-dimensional frames and numerous ZnO nanoparticles were anchored in the three-dimensional skeletons. Then, ZnO/PNT/rGO aerogels were calcined at 800 °C in the argon atmosphere, in which PNT/rGO were derived carbon aerogels, ZnO nanoparticles were reduced to Zn 0 by carbon, and generating zinc single atoms were captured by the surrounding nitrogen atoms or aggregated into Zn clusters/nanoparticles in the carbon substrates. The obtained products were Zn single atoms/clusters/ nanoparticles embedded into PNT/rGO-derived carbon aerogels, named Zn/NC catalysts. Zn/NC catalysts display a much higher half-wave potential and a larger limiting current density than pure rGO aerogels, NC, and Zn/C catalysts, indicating the synergy of excellent electronic transportation, high mass efficiency from outstanding porosity, and several active centers. Tailoring the quantity of zinc acetate can provide the optimal ORR performance with the E onset of 0.96 V, the E 1/2 of 0.845 V, and remarkable durability. This work exploits a novel strategy of carbon thermal reduction to construct high-performance Zn-based low-dimensional ORR catalysts.

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Conducting and Magnetic Composites Polypyrrole Nanotubes/Magnetite Nanoparticles: Application in Magnetorheology

Cited by 15 publications

References 55 publications

Stable Magnetorheological Fluids Containing Bidisperse Fillers with Compact/Mesoporous Silica Coatings

Stable Magnetorheological Fluids Containing Bidisperse Fillers with Compact/Mesoporous Silica Coatings

Magnetorheological properties of Fe–Co nanoparticles with high saturation magnetization and low coercivity

Zn Single Atoms/Clusters/Nanoparticles Embedded in the Hybrid Carbon Aerogels for High-Performance ORR Electrocatalysis

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