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2013年11月21日 Nature
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5 z! N8 `' A$ }9 @. {* QA water drop strikes the water-averse wing of a Morpho : t: a0 y5 A% f2 D5 j+ F2 w$ ]
butterfly. There are many uses for surfaces that can stay dry, self-clean or 4 Y5 y( i- y. W$ W0 Z+ }% {' T
resist icing. Liquid drops hitting such surfaces tend to spread out and then 7 l$ C! h2 M4 N9 h- }8 H x! o
retract before finally bouncing. Many applications benefit from minimizing the ) M; e- j' _6 V
contact time between drop and surface, which is generally assumed to occur if
# f9 V" ^+ e( B8 {the impacting drop deforms symmetrically. Kripa K. Varanasi and colleagues now 8 K' S& L" k% p, k
show that drops bounce off faster from a superhydrophobic surface with a
6 _8 y0 J3 M: J9 L2 t9 X# K: omorphology that redistributes the liquid mass so that it no longer spreads and
5 Y" F; E" ]; W. @4 s. u- kretracts symmetrically. Theory and experiments confirm that this strategy
6 [8 E! g# i/ [9 Qshortens the contact time between a bouncing drop and a surface beyond what was
_7 I$ s9 o# H; O- y9 A0 P2 Lthought possible. Photo: A. T. Paxson, K. Hounsell, J. W. Bales, J. C. Bird
, h* i4 H, J; g1 b& K. Varanasi.% f5 w5 O; X- G- }
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发表于 2013-11-22 18:25
发表于 2013-11-23 19:31
