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2013年11月21日 Nature
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6 ~; x# P! o' y. ZA water drop strikes the water-averse wing of a Morpho
& J: G$ ?8 L" d6 Bbutterfly. There are many uses for surfaces that can stay dry, self-clean or - M! L7 B5 m. k
resist icing. Liquid drops hitting such surfaces tend to spread out and then
. r! H/ c8 y) |7 |3 q- A' x/ Jretract before finally bouncing. Many applications benefit from minimizing the
, d' m' E; B7 j! acontact time between drop and surface, which is generally assumed to occur if ; l! S, x7 [0 ]# \$ a: m% J! {
the impacting drop deforms symmetrically. Kripa K. Varanasi and colleagues now
# U4 u8 k9 c5 Q+ mshow that drops bounce off faster from a superhydrophobic surface with a
F* v8 V, W8 a3 Y6 r* r' Dmorphology that redistributes the liquid mass so that it no longer spreads and
# m2 S. o# O2 |4 iretracts symmetrically. Theory and experiments confirm that this strategy + n. t" l) o9 x2 y0 X
shortens the contact time between a bouncing drop and a surface beyond what was ' m6 f' }+ @) J1 f, ?; V/ ~4 E! {: d% }
thought possible. Photo: A. T. Paxson, K. Hounsell, J. W. Bales, J. C. Bird . C: s, f) T2 ^( t3 B3 Z
& K. Varanasi.
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9 [( n: } q- [' L$ c, p3 b) F g. u
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发表于 2013-11-22 18:25
发表于 2013-11-23 19:31
