Magnetorheology of hybrid colloids obtained by spin-coating and classical rheometry
| Autor: | Wenceslao González-Viñas, Juan de Vicente, Keshvad Shahrivar, Raheema Aslam |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Spin coating Materials science Rheometry Polymer science digestive oral and skin physiology magnetorheology 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics Physics::Fluid Dynamics Condensed Matter::Soft Condensed Matter Mechanics of Materials Spin-coating 0103 physical sciences Signal Processing General Materials Science Colloids Electrical and Electronic Engineering 0210 nano-technology Civil and Structural Engineering |
| Zdroj: | Dadun. Depósito Académico Digital de la Universidad de Navarra instname |
| Popis: | Hybrid colloids composed of micron-sized ferromagnetic (carbonyl iron) and diamagnetic (silica) particles suspended in cyclohexanone, behave as, non-Newtonian, magnetorheological fluids. We measure and compare the magnetic field-dependent viscosity of hybrid diluted colloids using spin-coating and conventional magnetorheometry. We extend a previously developed model for simple colloids to this kind of hybrid colloids. As in the previous model, the viscosity of the colloidal suspension under applied fields can be derived from the surface coverage of the dry spin-coated deposits for each type of particles, and from the viscosity of the colloid at zero field. Also, our results allow us to obtain the evaporation rate of the solvent as a function of the rotation speed. Finally, we also measure the viscosity of the same suspension with a torsional parallel plate magnetorheometer under uniaxial DC magnetic fields aligned in the velocity gradient direction of a steady shearing flow. The experimental results under different conditions and the effect of each component on the magnetorheological properties of the resulting colloid are discussed. Standard spin-coating technique can be used both to characterize smart materials - complex fluids as well as to fabricate films with arbitrary solvents by tuning their viscosity by means of external fields. |
| Databáze: | OpenAIRE |
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