In this paper, we study the shear-induced flow of magneto-polymer composites, consisting of dispersions of magnetic particles in solutions of polymers, as a competition between the colloidal forces amid particles and their bulk transport induced by the hydrodynamic forces. For this aim, we analyse the role of different experimental parameters. Firstly, by using only solutions of a well-known anionic polymer (sodium alginate), we provoke a moderate hindering of particle movement, but keeping the liquid-like state of the samples. On the contrary, a gel-like behaviour is conferred to the samples when a cationic polymer (chitosan) is additionally added, which further reduces the particle movement. We analyse the effect of an applied magnetic field, which is opposed to particle transport by hydrodynamic forces, by inducing magnetic attraction between the particles. We perform the analysis under both stationary and oscillatory shear. We show that by using dimensionless numbers the differences between samples and experimental conditions are emphasized. In all cases, as expected, the transport of particles driven by bulk hydrodynamic forces dominates at high values of the shear rate.

This article is part of the theme issue ‘Transport phenomena in complex systems (part 1)’.

在本文中，我们研究了由磁性粒子在聚合物溶液中的分散体组成的磁性聚合物复合材料的剪切诱导流动，作为粒子之间的胶体力与其由流体动力引起的整体传输之间的竞争。为此，我们分析了不同实验参数的作用。首先，通过仅使用众所周知的阴离子聚合物（海藻酸钠）的溶液，我们会适度阻碍粒子运动，但保持样品的液体状态。相反，当额外添加阳离子聚合物（壳聚糖）时，样品具有凝胶状行为，这进一步减少了颗粒运动。我们分析了外加磁场的影响，它与流体动力作用下的粒子传输相反，通过在粒子之间产生磁引力。我们在固定剪切和振荡剪切下进行分析。我们表明，通过使用无量纲数，可以强调样品和实验条件之间的差异。在所有情况下，正如预期的那样，由大量流体动力驱动的颗粒传输在高剪切速率值下占主导地位。

本文是主题问题“复杂系统中的传输现象（第 1 部分）”的一部分。