Magnetic Nanorods for Optofluidic Applications

Tokarev, Alexander; Rubin, Binyamin; Bedford, Monte S.; Kornev, Konstantin G.

doi:10.1063/1.3530013

Cited by 17 publications

(34 citation statements)

References 12 publications

(24 reference statements)

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“…A few millitesla fields are sufficient enough to rotate magnetic nanoparticles. 8,21 In our experiments, we examined the performance of four, three, and two magnetic coils. The software developed in LABVIEW is able to produce three types of magnetic fields: rotating, pulsating, and dc fields.…”

Section: Design Of the Magnetic Rotatormentioning

confidence: 99%

“…Therefore, knowing the critical frequency and geometrical parameters of the nanorod, one can measure either fluid viscosity (provided that the magnetic moment M is known) or the nanorod magnetic moment (provided that the fluid viscosity is known). 8,15 Equation (7) is the fundamental equation of magnetic rotational spectroscopy (MRS) for the analysis of viscous fluids with nanorods. 15,37 …”

Section: Fig 3 Integral Curves Of Eq (4) Showing the Solution Behamentioning

confidence: 99%

“…24,[30][31][32] Magnetic rotators with small Helmholtz coils can provide the rotation frequency in the range between 1 Hz to 1 kHz and the ten millitesla field strength. 8,15,21,25,26,28,29,33 The strength and frequency of magnetic field are limited by the coil ability to support high currents. It was shown that small watercooled magnetic coils can maintain sufficiently high rotating magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

“…Such applications call for the development of new devices providing controlled manipulation of the objects in question. [4][5][6][7][8] Depending on the method of field generation, these devices can be split into two groups. [9][10][11] One group employs permanent magnets fixed on a movable stage/holder which can be shaken or spun to produce an ac field.…”

Section: Introductionmentioning

confidence: 99%

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Multifunctional magnetic rotator for micro and nanorheological studies

Tokarev

Aprelev

Zakharov

et al. 2012

Review of Scientific Instruments

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We report on the development of a multifunctional magnetic rotator that has been built and used during the last five years by two groups from Clemson and Drexel Universities studying the rheological properties of microdroplets. This magnetic rotator allows one to generate rotating magnetic fields in a broad frequency band, from hertz to tens kilohertz. We illustrate its flexibility and robustness by conducting the rheological studies of simple and polymeric fluids at the nano and microscale. First we reproduce a temperature-dependent viscosity of a synthetic oil used as a viscosity standard. Magnetic rotational spectroscopy with suspended nickel nanorods was used in these studies. As a second example, we converted the magnetic rotator into a pump with precise controlled flow modulation. Using multiwalled carbon nanotubes, we were able to estimate the shear modulus of sickle hemoglobin polymer. We believe that this multifunctional magnetic system will be useful not only for micro and nanorheological studies, but it will find much broader applications requiring remote controlled manipulation of micro and nanoobjects.

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Section: Design Of the Magnetic Rotatormentioning

confidence: 99%

Section: Fig 3 Integral Curves Of Eq (4) Showing the Solution Behamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multifunctional magnetic rotator for micro and nanorheological studies

Tokarev

Aprelev

Zakharov

et al. 2012

Review of Scientific Instruments

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“…For a ferromagnetic nanowire, researchers have shown that the magnetic torque could be quantitatively calculated [7][8][9]. However, there were different models to compute the fluid torque [10][11][12]. In previous studies,…”

Section: Introductionmentioning

confidence: 99%

Fluid resistance characteristics research of nanowire rotation under a magnetic field

Yang

Zhao

2015

J. Therm. Sci.

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In this study, a visualization-based experiment was performed to measure the motion of the nanowire under a magnetic field. A simulation method based on a multiple reference frame model (MRF model) was used to calculate fluid torque. Here, it was validated with the experimental data and theoretical results. Fluid torque of steady rotated nanowire was simulated and compared using experiment and theoretical models. The unsteady rotated condition was studied using transient simulation to compare with theory and the results showed that the acceleration of nanowire did not affect the flow field, indicating that the theoretical models based on the steady condition were still valid. The influence of solid walls on nanowire rotation was also studied here. The results showed that if the nanowire was placed close to the wall, the viscous force of wall would increase the velocity gradient around the nanowire, causing higher torque predictions. The fluid torque decreased quickly when the vertical distance between nanowire and wall exceeded 5 times the diameter of the wire.

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Ferromagnetic Nanorods in Applications to Control of the In‐Plane Anisotropy of Composite Films and for In Situ Characterization of the Film Rheology

Kornev

2016

Adv Funct Materials

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3796 wileyonlinelibrary.com nanorods as the fi llers are believed to be the best candidates for materials working in extreme environment and hence they are on demand in aerospace and space exploration applications. [39][40][41][42][43] In composite fi lms needed for inductor and antennae applications, the alignment of magnetic particles is required to increase the high frequency permeability and to lower the hysteresis losses. [44][45][46][47] In applications to manufacturing of high density recording fi lms and discs, spin alignment is required to carry the recorded information when spins in magnetic nanorods are prone to align parallel to the nanorod axis. [ 37,[48][49][50] In optical applications, magnetic liquid crystals are attractive candidates for making reconfi gurable magnetooptical devices with the fast time response measured in milliseconds. [11][12][13][14][15][16][17][18][51][52][53] In all these applications, one needs to control the alignment of magnetic nanorods in liquid medium. Therefore, this problem is actively discussed in the literature; however, the general strategy for making macroscopic samples with ordered nanorods has not been developed yet and it remains the main challenge of materials engineering [32][33][34][35][39][40][41][42]54 ] Processing of multifunctional coatings and thin fi lms require many steps and hence one needs to control the fi lm properties at each step.Rheological properties of the fi lms at each stage of their processing play the most important role in nanorod ordering and keeping nanorods in place. Characterization of thin coating fi lms during composite manufacturing remains challenging. Different experimental methods have been proposed and developed for in situ characterization of rheological properties of thin fi lms and coatings. [ 20,[25][26][27][55][56][57][58][59][60] It appears that unique features of rotation of ferromagnetic nanorods can be used for characterization of very thin fi lms when other methods fall short. Recently introduced magnetic rotational spectroscopy (MRS) with nanoparticles and nanorods allows one to probe fl uid rheology in very thin fi lms and nanoliter droplets. [ 12,20,22,25,60,61 ] MRS takes advantage of a distinguishable behavior of rotating magnetic tracers as the frequency of applied rotating fi eld changes. Unlike many methods based on the analysis of small oscillations, which are diffi cult to interpret when the fi lm is very thin, MRS with magnetic nanorods enjoys analysis of full revolutions of magnetic tracers. [ 20,22,24,25,60,62,63 ] Understanding of the characteristic features of rotation of a single nanorod in complex fl uids and alignment of an assembly

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Magnetic Nanorods for Optofluidic Applications

Cited by 17 publications

References 12 publications

Multifunctional magnetic rotator for micro and nanorheological studies

Multifunctional magnetic rotator for micro and nanorheological studies

Fluid resistance characteristics research of nanowire rotation under a magnetic field

Ferromagnetic Nanorods in Applications to Control of the In‐Plane Anisotropy of Composite Films and for In Situ Characterization of the Film Rheology

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