Investigation of the microscopic reason for the magnetoviscous effect in ferrofluids studied by small angle neutron scattering
Investigation of the microscopic reason for the magnetoviscous effect in ferrofluids studied by small angle neutron scattering
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小角中子散射研究铁磁流体磁粘效应的微观原因
DOI：
10.1088/0953-8984/18/38/s17
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
S. Odenbach
中科院分区：
文献类型：
--
作者：
L. Pop;S. Odenbach
对不同铁磁流体样品在剪切流动下的实验研究表明，磁场强度的增加会导致流体粘度的增加，即所谓的磁粘性效应，而剪切速率的增加会导致粘度的降低。粘度随磁场强度的变化可以从理论上解释为链状结构形成的影响，因此可以与铁磁流体微观结构的改性有关。利用专门设计的流变仪，用小角中子散射（SANS）对不同磁粘性效应的铁磁流体进行了研究。散射强度与流体结构形成相关，仅在具有高磁粘性效应的流体中随磁场和剪切速率的变化而变化。所得结果与解释磁粘性效应的定性模型吻合良好，表明铁磁流体的流变行为与其微观结构之间有很强的联系。
Experimental studies made on different ferrofluid samples under shear flow have shown that an increase of magnetic field strength yields an increase of the fluid’s viscosity, the so-called magnetoviscous effect, while increasing shear rate leads to a decrease of the viscosity. The change of the viscosity with magnetic field strength can be theoretically explained as an effect of chain-like structure formation and therefore can be related to the modification of the microstructure of ferrofluids. Using a specially designed rheometer, ferrofluids having different magnitude of the magnetoviscous effect were investigated by small angle neutron scattering (SANS). Correlated to the structure formation in the fluid, the scattered intensity shows a variation with magnetic field and shear rate only for fluids with a high magnetoviscous effect. The results obtained show a good agreement with the qualitative model elaborated to explain the magnetoviscous effect, indicating a strong connection between the rheological behaviour of ferrofluids and their microstructure.