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- 积分
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2013年11月21日 Nature8 }/ O, p: k# O$ r Q# V/ J7 B
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A water drop strikes the water-averse wing of a Morpho ( u8 D( y9 p/ c5 J0 t- R
butterfly. There are many uses for surfaces that can stay dry, self-clean or
* F! j; G& ?# Q2 j. [resist icing. Liquid drops hitting such surfaces tend to spread out and then 7 S" O" |: z% d, X' `
retract before finally bouncing. Many applications benefit from minimizing the 0 f9 c; I( I1 r7 t4 s/ I9 a
contact time between drop and surface, which is generally assumed to occur if 7 f3 Y& `5 Q' ?
the impacting drop deforms symmetrically. Kripa K. Varanasi and colleagues now 4 [. f: g# W4 ?, h, k9 H
show that drops bounce off faster from a superhydrophobic surface with a 4 Y, a# A0 X. K' P, A0 S. L
morphology that redistributes the liquid mass so that it no longer spreads and 4 G8 T! f7 j3 D9 J. C; v
retracts symmetrically. Theory and experiments confirm that this strategy
4 Z$ I. ?, t. I' `9 u: ~7 Pshortens the contact time between a bouncing drop and a surface beyond what was % ^( r$ Y' O( {& Z
thought possible. Photo: A. T. Paxson, K. Hounsell, J. W. Bales, J. C. Bird
( X& p% M* o3 R0 v& K. Varanasi.
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发表于 2013-11-22 18:25
发表于 2013-11-23 19:31
