The work describes the experimental and theoretical investigation of water drop impact onto electrospun polymer nanofiber mats deposited on heated stainless steel foils. The measurements encompass water spreading over and inside the mat, as well as the corresponding thermal field. The results show that the presence of polymer nanofiber mats prevents receding motion of drops after their complete spreading and promotes the moisture spreading inside the mat over a large area of the heater, which facilitates a tenfold enhancement of heat removal as the latent heat of drop evaporation.

The Leidenfrost effect is a technically and industrially important phenomenon that severely restricts heat removal from high-heat-flux surfaces. A simple remedy to the Leidenfrost effect is provided by polymer nanofiber mats created and deposited by electrospinning on stainless steel surfaces. The influence of nanofiber mats on hydrodynamics and cooling efficiency of single drop impact onto hot surfaces has been investigated experimentally. The evolution of the drops has been recorded by a high-speed complimentary metal-oxide semiconductor camera, whereas the cooling temperature was measured by a thermocouple. A remarkable phenomenon was discovered: a mat of polymer nanofibers electrospun onto a heater surface can completely suppress the Leidenfrost effect, thereby increasing the rate of heat removal from the surface to the liquid drops significantly. The "inverse-Leidenfrost" effect is described qualitatively and quantitatively, providing clear physical reasons for the observed behavior.

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This study is focused on the stretching and breakup of a Newtonian liquid bridge between two parallel plates, one of which moves with a constant acceleration. The experimental device is designed to achieve high acceleration (up to 200 m s −2 ) with high precision. The shape evolution of the liquid bridge and its pinch-off are captured using a high-speed video system. At high enough acceleration the evolution of the midpoint diameter of the bridge is universal; it depends neither on the acceleration nor on the liquid viscosity. Moreover, at high acceleration rates even the breakup time does not depend on the acceleration, but is determined solely by the liquid viscosity. A model is proposed which predicts the instant of the liquid bridge pinch-off. Finally, the volumes of the residual liquid on both fixed and moving plates (which do not include the total volume of the residual secondary drops) is measured. It is shown that the volume on the fixed plate remains almost constant, the volume on the accelerating plate reduces as the acceleration increases.