Assessing magnetic nanoparticle aggregation in polymer melts by dynamic magnetic susceptibility measurements

Sierra-Bermúdez, Sergio; Maldonado-Camargo, Lorena; Orange, François; Guinel, Maxime J.-F.; Rinaldi, Carlos

doi:10.1016/j.jmmm.2014.10.171

Cited by 13 publications

(9 citation statements)

References 76 publications

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“…S1). Similarly to our observations, complex MNP structure has been reported previously in photopolymer matrix and other polymer solutions and melts . Robbes et al have proposed that aggregation of MNPs in a liquid polymer matrix undergoes a two‐step aggregation process.…”

Section: Resultssupporting

confidence: 91%

Translation of segment scale stiffening into macroscale reinforcement in polymer nanocomposites

Zbončák

Ondreáš

Uhlíř

et al. 2019

Polymer Engineering & Sci

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Structuring of polymer nanocomposites (PNCs) with an aid of relatively weak external magnetic fields has been studied as a method for control of the nano‐ and microstructure. Magnetic nanoparticles (NPs) were assembled into high aspect ratio one‐dimensional strings and unidirectionally oriented with the magnetic field (B = 0–50 mT) within the photopolymer matrix. The effect of the anisotropic MNPs assemblies on the mechanical properties was studied over a wide temperature range for the first time. The impact of various reinforcing mechanisms was distinguished with respect to the position of the glass transition temperature (Tg). The reinforcing effect exhibits temperature dependency with a maximum ~65°C above the glass transition and only negligible effect below the Tg. In addition, significant directional anisotropy of stiffness was observed. Composite micromechanics was applied to interpret the orientation and size‐dependent reinforcement of PNCs, and temperature‐dependent stiffness of the polymer‐MNP structures was quantified. The presence of polymer chains with altered dynamics surrounding the MNPs inside the anisotropic assemblies was proposed to be an essential nanoscale mechanism mediating the stress transfer and contributing to mechanical robustness of the hybrid structures and PNCs. POLYM. ENG. SCI., 60:587–596, 2020. © 2019 Society of Plastics Engineers

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Section: Resultssupporting

confidence: 91%

Translation of segment scale stiffening into macroscale reinforcement in polymer nanocomposites

Zbončák

Ondreáš

Uhlíř

et al. 2019

Polymer Engineering & Sci

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“…Because the measurement principle is magnetic and highly sensitive to changes in rotational diffusivity, the technique can be applied to small (50–200 μL) and optically complex samples. Previously, this technique has been used to detect the presence of MNPs aggregates in polymer melts and to monitor adsorption of proteins to MNPs by changes in the rotational diffusitivity of the nanoparticles. , DMS measurements of suitably synthesized MNPs could also be used to sense porperties in polymer melts such as phase transitions of polymer matrices and nanoscale viscosity of small solvent fluids. − Finally, DMS measurements have been used to evaluate the mobility of nanoparticles in polymer solutions and hydrogels. , …”

Section: Estimating Nanoparticle Rotational Diffusivity Through Dynam...mentioning

confidence: 99%

Breakdown of the Stokes–Einstein Relation for the Rotational Diffusivity of Polymer Grafted Nanoparticles in Polymer Melts

Maldonado-Camargo

Rinaldi

2016

Nano Lett.

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We report observations of breakdown of the Stokes-Einstein relation for the rotational diffusivity of polymer-grafted spherical nanoparticles in polymer melts. The rotational diffusivity of magnetic nanoparticles coated with poly(ethylene glycol) dispersed in poly(ethylene glycol) melts was determined through dynamic magnetic susceptibility measurements of the collective rotation of the magnetic nanoparticles due to imposed time-varying magnetic torques. These measurements clearly demonstrate the existence of a critical molecular weight for the melt polymer, below which the Stokes-Einstein relation accurately describes the rotational diffusivity of the polymer-grafted nanoparticles and above which the Stokes-Einstein relation ceases to apply. This critical molecular weight was found to correspond to a chain contour length that approximates the hydrodynamic diameter of the nanoparticles.

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“…Thus, ACS measurements as a function of field frequency enable determination of the Brownian relaxation time and subsequently the hydrodynamic size of the particles using equation (2) above. Using this versatile characterization method, the formation of protein corona around MNPs caused by their surface charge 18,19 , the aggregation of MNPs within polymer nanocomposites 20 , and the mobility of MNPs in cells 19,21,22 , have been explored previously. Figure 1: Schematic showing the AC susceptibility versus frequency curve expected for blocked magnetic nanoparticles displaying Brownian relaxation.…”

Section: Introductionmentioning

confidence: 99%

Alternating current (AC) susceptibility as a particle-focused probe of coating and clustering behaviour in magnetic nanoparticle suspensions

Narayanasamy

Cruz‐Acuña

Everett

et al. 2018

Journal of Colloid and Interface Science

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Assessing magnetic nanoparticle aggregation in polymer melts by dynamic magnetic susceptibility measurements

Cited by 13 publications

References 76 publications

Translation of segment scale stiffening into macroscale reinforcement in polymer nanocomposites

Translation of segment scale stiffening into macroscale reinforcement in polymer nanocomposites

Breakdown of the Stokes–Einstein Relation for the Rotational Diffusivity of Polymer Grafted Nanoparticles in Polymer Melts

Alternating current (AC) susceptibility as a particle-focused probe of coating and clustering behaviour in magnetic nanoparticle suspensions

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