Supramolecular magnetorheological polymer gels

Abstract

Novel magnetorheological fluids-supramolecular magnetorheological polymer gels (SMRPGs)-were investigated. Supramolecular polymer deposited on the surface of iron particles was suspended in the carrier fluids. The supramolecular network was obtained by metal coordination between terpyridine monomers and zinc ion. These SMRPGs had such advantages as controllable off-state viscosity, a reduced iron particle settling rate, and stability. The viscoelastic behavior of SMRPGs with small-and largeamplitude oscillatory shear was investigated using the amplitude and frequency sweep mode. The effects of strain amplitude, frequency, and magnetic field strength on the viscoelastic moduli were measured. The linear viscoelastic (LVE) strain range was obtained by the oscillation and static stress strain methods. The maximum LVE value was equal to the preyield strain point, 0.3%. Microstructural variation of SMRPG is proposed as an explanation of the rheological changes in the oscillation tests. The results of this research indicate that off-state viscosity and particle settling can be controlled by adjusting the concentration of supramolecular polymer gel. Dynamic yield stress significantly increased with an external magnetic field up to ϳ23,500 Pa under a magnetic flux density of 500 mT.

Clinical outcomes with contemporary endovascular therapy of iliac artery occlusive disease

“…For this purpose, solutions of bis(terpyridine)s 1–10 in NMP (10 wt %) have been taken as references and viscosities η ranging from 5.2 to 7.1 mPa s have been determined. The metallopolymers P1–P10 have exhibited an increased viscosity by an average factor of about 1.6 relative to those of 1–10 what is in good agreement with similar reports known from literature 16(b,c), 26. P1–P10 have shown viscosities η between 8 and 11.5 mPa·s (Table 2).…”

Study on the properties of magnetorheological gel based on polyurethane

“…It also proved that viscoelastic properties of PU MRG were affected by the microstructure of iron particles. which shows a good agreement with Hu et al20…”

“…Magnetorheological gel (MRG), which is a composite fluid of magnetic particles suspended in polymer gels, is known as a new generation of MRFs and used in vibration control and damping devices 19. These fluids have the advantages of being able to control off‐state viscosity and to reduce the settling rate of the magnetic particles in the fluid 20. And with the precipitation of polymeric gel on the surface of the iron particles, the stability of the system can be improved 17…”

Improved rheological properties of dimorphic magnetorheological gels based on flower-like carbonyl iron particles

“…As an intermediate material between MR fluids and MR elastomers, its rheological and mechanical properties, such as the yield stress, viscosities and dynamic mechanical properties, can also be controlled rapidly, continuously and reversibly by the external magnetic field [2,3]. In addition, due to the fact that nonmagnetic matrix is replaced by the partially crosslinked polymer gel with high viscosity, the MRGs can overcome the settling of particles and has better application stability than that of the MR fluids [4,5]. Meanwhile, compared with MR elastomers, MRGs have a higher relative MR effect which up to 6000% [6,7].…”

“…To date, a number of researchers have carried out some research on the material properties and potential applications of MRGs. Hu et al [4] studied the viscoelastic behavior of MRGs under the amplitude and frequency sweep mode using a MR rheometer, experiments show that the dynamic shear yield stress increased dramatically with the external magnetic field and can up to a value of 23.5KPa at 500mT. Shin et al [16] designed and investigated a tunable vibration absorber (TVA) based on MRGs, the experiment validated that the MRGs TVA has a tuning range from 33Hz to 40Hz when the magnetic flux density was 120mT and a wider tuning range is likely to be obtained by applying a larger magnetic field.…”