Leaf Surface Wettability and Implications for Drop Shedding and Evaporation from Forest Canopies
Leaf Surface Wettability and Implications for Drop Shedding and Evaporation from Forest Canopies
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DOI：
10.1007/s00024-011-0330-2
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发表时间：
2012-05-01
影响因子：
2
通讯作者：
Roth-Nebelsick, A.
中科院分区：
文献类型：
--
作者：
Konrad, W.;Ebner, M.;Roth-Nebelsick, A.
林冠截留雨露、雾的能力主要取决于林冠的吸湿能力和叶表的持水能力。与通常的预期相反，叶子的疏水性或润湿性并不决定水滴对叶子的粘性。对于液滴的粘附至关重要的是接触角滞后，即对于运行液滴的前缘接触角和后缘接触角之间的差。取决于静态接触角的其他参数是可以粘附到表面的液滴的最大体积和粘附液滴相对于蒸发的持久性。接触角和接触角滞后的适应性允许人们追求不同的液滴控制策略，例如有效的水脱落或最大限度地保留粘附的水。如果接触角滞后低，则实现有效的水脱落。（孤立的）大液滴的保持需要高接触角滞后和65.5A度的静态接触角，而通过液滴的最佳间距的最大保持需要高接触角滞后和111.6A度的静态接触角。如果静态接触角达到77.5A度，则获得相对于蒸发的最大持久性，同时具有高接触角滞后。可以预期，了解这些参数有助于提高森林的截水能力。
Wettability and retention capacity of leaf surfaces are parameters that contribute to interception of rain, fog or dew by forest canopies. Contrary to common expectation, hydrophobicity or wettability of a leaf do not dictate the stickiness of drops to leaves. Crucial for the adhesion of drops is the contact angle hysteresis, the difference between leading edge contact angle and trailing edge contact angle for a running drop. Other parameters that are dependent on the static contact angle are the maximum volume of drops that can stick to the surface and the persistence of an adhering drop with respect to evaporation. Adaption of contact angle and contact angle hysteresis allow one to pursue different strategies of drop control, for example efficient water shedding or maximum retention of adhering water. Efficient water shedding is achieved if contact angle hysteresis is low. Retention of (isolated) large drops requires a high contact angle hysteresis and a static contact angle of 65.5A degrees, while maximum retention by optimum spacing of drops necessitates a high contact angle hysteresis and a static contact angle of 111.6A degrees. Maximum persistence with respect to evaporation is obtained if the static contact angle amounts to 77.5A degrees, together with a high contact angle hysteresis. It is to be expected that knowledge of these parameters can contribute to the capacity of a forest to intercept water.