skip to main content

SciTech ConnectSciTech Connect

Title: Magnetic and elastic anisotropy in magnetorheological elastomers using nickel-based nanoparticles and nanochains

Nickel (Ni) based nanoparticles and nanochains were incorporated as fillers in polydimethylsiloxane (PDMS) elastomers and then these mixtures were thermally cured in the presence of a uniform magnetic field. In this way, macroscopically structured-anisotropic PDMS-Ni based magnetorheological composites were obtained with the formation of pseudo-chains-like structures (referred as needles) oriented in the direction of the applied magnetic field when curing. Nanoparticles were synthesized at room temperature, under air ambient atmosphere (open air, atmospheric pressure) and then calcined at 400 °C (in air atmosphere also). The size distribution was obtained by fitting Small Angle X-ray Scattering (SAXS) experiments with a polydisperse hard spheres model and a Schulz-Zimm distribution, obtaining a size distribution centered at (10.0 ± 0.6) nm with polydispersivity given by σ = (8.0 ± 0.2) nm. The SAXS, X-ray powder diffraction, and Transmission Electron Microscope (TEM) experiments are consistent with single crystal nanoparticles of spherical shape (average particle diameter obtained by TEM: (12 ± 1) nm). Nickel-based nanochains (average diameter: 360 nm; average length: 3 μm, obtained by Scanning Electron Microscopy; aspect ratio = length/diameter ∼ 10) were obtained at 85 °C and ambient atmosphere (open air, atmospheric pressure). The magnetic properties of Ni-based nanoparticles and nanochains at room temperature are compared and discussed in terms of surface and size effects. Both Ni-basedmore » nanoparticles and nanochains were used as fillers for obtaining the PDMS structured magnetorheological composites, observing the presence of oriented needles. Magnetization curves, ferromagnetic resonance (FMR) spectra, and strain-stress curves of low filler's loading composites (2% w/w of fillers) were determined as functions of the relative orientation with respect to the needles. The results indicate that even at low loadings it is possible to obtain magnetorheological composites with anisotropic properties, with larger anisotropy when using nanochains. For instance, the magnetic remanence, the FMR field, and the elastic response to compression are higher when measured parallel to the needles (about 30% with nanochains as fillers). Analogously, the elastic response is also anisotropic, with larger anisotropy when using nanochains as fillers. Therefore, all experiments performed confirm the high potential of nickel nanochains to induce anisotropic effects in magnetorheological materials.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Instituto de Química Física de Materiales, Ambiente y Energía (INQUIMAE), Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires (Argentina)
  2. Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina)
  3. Centro Atómico Bariloche (Comisión Nacional de Energía Atómica. Argentina) and Instituto Balseiro, Universidad Nacional de Cuyo, Mendoza (Argentina)
  4. Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires (Argentina)
  5. Grupo de Fluidos Complexos, Instituto de Física, Universidade de São Paulo, São Paulo (Brazil)
Publication Date:
OSTI Identifier:
22258693
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ANISOTROPY; ATMOSPHERIC PRESSURE; ELASTOMERS; FERROMAGNETIC RESONANCE; HARD-SPHERE MODEL; MAGNETIC FIELDS; MAGNETIC PROPERTIES; MONOCRYSTALS; NANOSTRUCTURES; NICKEL; SCANNING ELECTRON MICROSCOPY; SMALL ANGLE SCATTERING; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION