论文标题

无接触式胶体探针流变中厚的孔弹性凝胶的机械响应

Mechanical response of a thick poroelastic gel in contactless colloidal-probe rheology

论文作者

Kopecz-Muller, Caroline, Bertin, Vincent, Raphael, Elie, Mcgraw, Joshua D, Salez, Thomas

论文摘要

当刚性物体接近粘性液中的软材料时,润滑接触区域中会出现流体动力应力并变形软材料。弹性变形反过来修改流动,因此产生软润滑耦合。此外,柔软的弹性体和凝胶通常是多孔的。这些材料可能充满溶剂或非交联聚合物链,并且可能会渗透到周围的流体中,从而进一步使描述更加复杂。在这里,我们得出了半无限和可渗透的毛弹性底物的点反应。然后,我们使用这种基本解决方案来解决与非接触胶胶体探针方法相关的特定毛弹性润滑耦合。特别是,我们得出了与靠近毛弹性底物的球的振荡垂直运动相关的保守和耗散成分。我们的结果可能与软,生物和/或脆弱的材料(例如肿胀的水凝胶和生物膜)上的动态表面力设备和无接触式胶体原子力显微镜显微镜实验有关。

When a rigid object approaches a soft material in a viscous fluid, hydrodynamic stresses arise in the lubricated contact region and deform the soft material. The elastic deformation modifies in turn the flow, hence generating a soft-lubrication coupling. Moreover, soft elastomers and gels are often porous. These materials may be filled with solvent or uncrosslinked polymer chains, and might be permeable to the surrounding fluid, which complexifies further the description. Here, we derive the point-force response of a semi-infinite and permeable poroelastic substrate. Then, we use this fundamental solution in order to address the specific poroelastic lubrication coupling associated with contactless colloidal-probe methods. In particular, we derive the conservative and dissipative components of the force associated with the oscillating vertical motion of a sphere close to the poroelastic substrate. Our results may be relevant for dynamic surface force apparatus and contactless colloidal-probe atomic force microscopy experiments on soft, living and/or fragile materials, such as swollen hydrogels and biological membranes.

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