Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102852
Title: Influence of size polydispersity on magnetic field tunable structures in magnetic nanofluids containing superparamagnetic nanoparticles
Authors: Mohapatra, D. K.
Camp, P. J.
Philip, J.
Issue Date: 2021
Publisher: Royal Society of Chemistry
Citation: Mohapatra D. K. Influence of size polydispersity on magnetic field tunable structures in magnetic nanofluids containing superparamagnetic nanoparticles / D. K. Mohapatra, P. J. Camp, J. Philip. — DOI 10.1039/d1na00131k // Nanoscale Advances. — 2021. — Vol. 3. — Iss. 12. — P. 3573-3592.
Abstract: We probe the influence of particle size polydispersity on field-induced structures and structural transitions in magnetic fluids (ferrofluids) using phase contrast optical microscopy, light scattering and Brownian dynamics simulations. Three different ferrofluids containing superparamagnetic nanoparticles of different polydispersity indices (PDIs) are used. In a ferrofluid with a high PDI (∼0.79), thin chains, thick chains, and sheets are formed on increasing the in-plane magnetic field, whereas isotropic bubbles, and hexagonal and lamellar/stripe structures are formed on increasing the out-of-plane magnetic field over the same range. In contrast, no field-induced aggregates are seen in the sample with low polydispersity under the above conditions. In a polydisperse sample, bubbles are formed at a very low magnetic field strength of 30 G. Insights into the structural evolution with increasing magnetic field strength are obtained by carrying out Brownian dynamics simulations. The crossovers from isotropic, through hexagonal columnar, to lamellar/stripe structures observed with increasing field strength in the high-polydispersity sample indicate the prominent roles of large, more strongly interacting particles in structural transitions in ferrofluids. Based on the observed microstructures, a phase diagram is constructed. Our work opens up new opportunities to develop optical devices and access diverse structures by tuning size polydispersity. © The Royal Society of Chemistry 2021.
Keywords: BROWNIAN MOVEMENT
LIGHT SCATTERING
MAGNETIC FIELDS
MAGNETIC FLUIDS
NANOFLUIDICS
NANOPARTICLES
PARTICLE SIZE
POLYDISPERSITY
SUPERPARAMAGNETISM
VOLCANIC ROCKS
BROWNIAN DYNAMICS SIMULATIONS
IN-PLANE MAGNETIC FIELDS
INTERACTING PARTICLES
MAGNETIC FIELD STRENGTHS
OUT-OF-PLANE MAGNETIC FIELDS
POLYDISPERSITY INDICES
STRUCTURAL TRANSITIONS
SUPERPARAMAGNETIC NANOPARTICLES
NANOMAGNETICS
URI: http://hdl.handle.net/10995/102852
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85107906296
PURE ID: 22104245
9df0704a-cd5d-4df6-be11-2bae1bf9538c
ISSN: 25160230
DOI: 10.1039/d1na00131k
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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