论文标题
粘弹性液体桥式破裂和两个表面之间的液体转移
Viscoelastic Liquid Bridge Breakup and Liquid Transfer Between two Surfaces
论文作者
论文摘要
我们通过实验研究了由聚（丙烯酸）水溶液制成的液体桥的分裂，它们在两个分离的固体表面之间具有自由移动的接触线。对于高于一定阈值的聚合物浓度（$ \ sim $ 30 ppm），在液体桥毛细管破裂之前，表面上的接触线完全缩回。这意味着，当表面分离时，所有液体都保持在相对表面上。无论研究液体体积和拉伸速度的范围如何，都会发生这种行为。这种行为与有意固定接触线的牛顿液体或非牛顿系统的行为有很大不同。结果表明，这种行为源于桥颈稀疏（因延伸增厚而延迟）与接触线的退缩（通过剪切稀疏增强）之间的竞争，而较低的接触角。如果两个表面具有相同的润湿特性，则由于重力引起的不对称性，上部接触线在毛细血管破裂前完全缩回，因此，所有液体都保持在下表面。
We studied experimentally the breakup of liquid bridges made of aqueous solutions of Poly(acrylic acid) between two separating solid surfaces with freely moving contact lines. For polymer concentrations higher than a certain threshold ($\sim$ 30 ppm), the contact line on the surface with the highest receding contact angle fully retracts before the liquid bridge capillary breakup takes place at its neck. This means that all the liquid remains attached to the opposing surface when the surfaces are separated. This behavior occurs regardless of the range of liquid volume and stretching speed studied. Such behavior is very different from that observed for Newtonian liquids or non-Newtonian systems where contact lines are intentionally pinned. It is shown that this behavior stems from the competition between thinning of bridge neck (delayed by extensional thickening) and receding of contact line (enhanced by shear thinning) on the surface with lower receding contact angle. If the two surfaces exhibit the same wetting properties, the upper contact line fully retracts before the capillary breakup due to the asymmetry caused by gravity, and, therefore, all the liquid remains on the lower surface.
