The rebound of impinging droplets is a defining characteristic of superhydrophobic surfaces; yet, such an intriguing interfacial phenomenon can be effectively suppressed by adding a tiny amount of flexible polymers to induce non-Newtonian viscoelastic properties. In this work, however, we demonstrate the promoting effects of surface heating on the rebound of impinging viscoelastic droplets on superhydrophobic surfaces. The underlying mechanism for the promotion is that the local heat transfer at the liquid–solid interface causes the fast evaporation of the liquid and thus the breakup of the formed viscoelastic filaments, which hinder droplet recoiling. Therefore, the lower threshold velocity for rebound increases while the upper threshold velocity for rebound suppression decreases with increasing surface temperature, resulting in a wider regime for droplet rebound in the impact phase diagram. The surface heating effect on liquid–solid interactions also leads to a nontrivial dependence of the contact time on the impact velocity and a linear decrease of the restitution coefficient with the Weber number for diverse bouncing viscoelastic droplets, which can be rationalized by coupling the interfacial force and energy analyses. We envision that these findings would be useful in technological processes requiring control the retention of viscoelastic liquids on solid surfaces.

撞击液滴的回弹是超疏水表面的主要特征。然而，通过添加少量的柔性聚合物来诱导非牛顿粘弹性，可以有效地抑制这种令人感兴趣的界面现象。然而，在这项工作中，我们证明了表面加热对超疏水表面上撞击的粘弹性液滴反弹的促进作用。促进作用的基本机制是，在液-固界面处的局部传热会导致液体快速蒸发，从而导致形成的粘弹性丝断裂，从而阻碍液滴回卷。因此，随着表面温度的升高，回弹的下限阈值速度增大，而回弹抑制的上限阈值速度减小，从而在碰撞相图中产生了更广泛的液滴回弹机制。表面加热对液-固相互作用的影响还导致接触时间对冲击速度的非平凡依赖，并且对于各种弹跳粘弹性液滴，恢复系数与韦伯数呈线性下降，这可以通过耦合界面力来合理化。和能量分析。我们设想这些发现将在要求控制粘弹性液体在固体表面上的保留的工艺过程中很有用。表面加热对液-固相互作用的影响还导致接触时间对冲击速度的非平凡依赖，并且对于各种弹跳粘弹性液滴，恢复系数与韦伯数呈线性下降，这可以通过耦合界面力来合理化。和能量分析。我们设想这些发现将在要求控制粘弹性液体在固体表面上的保留的工艺过程中很有用。表面加热对液-固相互作用的影响还导致接触时间对冲击速度的非平凡依赖，并且对于各种弹跳粘弹性液滴，恢复系数与韦伯数呈线性下降，这可以通过耦合界面力来合理化。和能量分析。我们设想这些发现将在要求控制粘弹性液体在固体表面上的保留的工艺过程中很有用。