Effect of polymer concentration on the dynamics of dilute polymer solution drops impacting on heated surfaces in the Leidenfrost regime

•We investigate the dynamics of Leidenfrost drops of dilute polymer solutions.•We show polymers change the impact morphology and dynamics.•The polymer concentration (fluid elasticity) does not have a significant effect.

The impact of dilute polymer solution drops (equilibrium diameter: ∼3 mm) on a hot surface in the Leidenfrost regime is studied experimentally by high-speed imaging, in the range of impact Weber numbers between 10 and 200, and compared with the impact of water drops in the same conditions. Dilute solutions of polyethylene oxide (PEO) in de-ionised water were used as model viscoelastic fluids, with polymer mass concentrations in the range 100–400 ppm. Results confirm previous findings showing that polymer additives cause a reduction of the maximum spreading diameter and an increase of the maximum bouncing height of drops already at low polymer concentrations. This suggests a different distribution of the initial impact kinetic energy with respect to drops of pure water. The analysis of drop oscillations does not show significant effects of the polymer concentration on the drop dynamic behaviour which is similar in Newtonian and in viscoelastic drops.