Mehrizi Abbasali Abouei, Lin Shiji, Sun Lijie, Wang Yile, Chen Longquan
School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Sci Rep. 2022 Jul 13;12(1):11920. doi: 10.1038/s41598-022-15645-1.
Spraying occurs by the impact of water droplets on the superhydrophobic wire meshes by liquid penetration during the spreading and recoiling. We have shown that adding a small amount of high molecular weight polymer (PEO) alters the ligaments formation and stabilizes them due to its high elasticity. Consequently, it suppresses droplet spray during droplet spreading and recoiling (recoil penetration). In the wide range of the impact velocities, the penetrated ligaments retracted back to the mesh after reaching the maximum length and eventually merged with the droplet on the mesh. The empirical fitting shows that the ligament evolution follows the parallel spring-dashpot model of Kelvin-Voigt. The additive polymer also changes the recoil penetration mechanisms from cavity collapse to cavity detachment due to the higher retraction velocity of the cavity near the mesh that is induced by the upward flow formed by the retraction of the ligaments to the mother droplet. A model based on mass conservation is proposed to calculate the variation of the maximum ligament size.
在铺展和回弹过程中，通过液体渗透，水滴撞击超疏水金属丝网时会发生喷雾现象。我们已经表明，添加少量高分子量聚合物（PEO）会改变韧带的形成，并由于其高弹性而使其稳定。因此，它抑制了液滴铺展和回弹（回弹渗透）过程中的液滴喷雾。在很宽的冲击速度范围内，穿透的韧带在达到最大长度后会缩回金属丝网，并最终与金属丝网上的液滴合并。经验拟合表明，韧带的演化遵循开尔文-沃伊特的平行弹簧-阻尼器模型。由于韧带向母液滴回缩形成的向上流动，导致靠近金属丝网的腔体回缩速度更高，添加的聚合物还将回弹渗透机制从腔体坍塌转变为腔体脱离。提出了一个基于质量守恒的模型来计算最大韧带尺寸的变化。
