Drop impact, spreading, splashing, and penetration into electrospun nanofiber mats

Andreas N. Lembach, Hung Bing Tan, Ilia V. Roisman, Tatiana Gambaryan-Roisman, Yiyun Zhang, Cameron Tropea, Alexander L. Yarin

Research output: Contribution to journalArticlepeer-review

120 Citations (Scopus)


Experiments were conducted to study peculiarities of drop impact onto electrospun polymer nanofiber mats. The nanofiber cross-sectional diameters were of the order of several hundred nanometers, the pore sizes in the mats of about several micrometers, and the mat thicknesses of the order of 200 μm. Polyacrylonitrile (PAN), a polymer which is partially wettable by water, was used to electrospin nanofiber mats. The experiments revealed that drop impact onto nanotextured surfaces of nanofiber mats produce spreading similar to that on the impermeable surfaces. However, at the end of the spreading stage, the contact line is pinned and drop receding is prevented. At higher impact velocities, prompt splashing events with formation of tiny drops were observed. It was shown that the splash parameter Kd=We1/2 Re 1/4 (with We and Re being the Weber and Reynolds numbers, respectively) previously used to characterize the experiments with drop impact onto smooth impermeable dry substrates can be also used to describe the onset of splash on substrates coated by nanofiber mats. However its threshold value Kds (in particular, corresponding to the minimal impact velocity leading to generation of secondary droplets) for the nanotextured surfaces is higher than that for dry flat substrates. In addition, water penetration and spreading inside wettable nanofiber mats after drop impact was elucidated and quantified. The hydrodynamics of drop impact onto nanofiber mats is important for understanding effective spray cooling through nanofiber mats, recently introduced by the same group of authors.

Original languageEnglish
Pages (from-to)9516-9523
Number of pages8
Issue number12
Publication statusPublished - 2010 Jun 15

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry


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