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- 26159
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2013年11月21日 Nature
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A water drop strikes the water-averse wing of a Morpho
2 ~* i) C5 w! ibutterfly. There are many uses for surfaces that can stay dry, self-clean or % n, h( g8 [( g' U! W; k+ _# O( R
resist icing. Liquid drops hitting such surfaces tend to spread out and then * a- K a% J* X
retract before finally bouncing. Many applications benefit from minimizing the
& O- }$ t2 q, J- u2 O" ?" vcontact time between drop and surface, which is generally assumed to occur if % M; O+ ]. i3 p h
the impacting drop deforms symmetrically. Kripa K. Varanasi and colleagues now / q4 k I( }. F% C% A
show that drops bounce off faster from a superhydrophobic surface with a % G( S3 c' Z1 s9 ]$ S, J
morphology that redistributes the liquid mass so that it no longer spreads and & f/ I8 L6 o% U9 W4 A! j4 N8 Q
retracts symmetrically. Theory and experiments confirm that this strategy * C$ ?+ L6 E% d' _$ g+ a
shortens the contact time between a bouncing drop and a surface beyond what was : d0 R0 A9 ]9 ]0 {# g
thought possible. Photo: A. T. Paxson, K. Hounsell, J. W. Bales, J. C. Bird 9 u" `+ E2 G/ R& J( j
& K. Varanasi.
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发表于 2013-11-22 18:25
发表于 2013-11-23 19:31
