Making a splash with water repellency

Physics – Condensed Matter – Soft Condensed Matter

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

accepted for publication in Nature Physics

Scientific paper

A 'splash' is usually heard when a solid body enters water at large velocity. This phenomena originates from the formation of an air cavity resulting from the complex transient dynamics of the free interface during the impact. The classical picture of impacts on free surfaces relies solely on fluid inertia, arguing that surface properties and viscous effects are negligible at sufficiently large velocities. In strong contrast to this large-scale hydrodynamic viewpoint, we demonstrate in this study that the wettability of the impacting body is a key factor in determining the degree of splashing. This unexpected result is illustrated in Fig.1: a large cavity is evident for an impacting hydrophobic sphere (1.b), contrasting with the hydrophilic sphere's impact under the very same conditions (1.a). This unforeseen fact is furthermore embodied in the dependence of the threshold velocity for air entrainment on the contact angle of the impacting body, as well as on the ratio between the surface tension and fluid viscosity, thereby defining a critical capillary velocity. As a paradigm, we show that superhydrophobic impacters make a big 'splash' for any impact velocity. This novel understanding provides a new perspective for impacts on free surfaces, and reveals that modifications of the detailed nature of the surface -- involving physico-chemical aspects at the nanometric scales -- provide an efficient and versatile strategy for controlling the water entry of solid bodies at high velocity.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Making a splash with water repellency does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Making a splash with water repellency, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Making a splash with water repellency will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-15934

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.