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我国学者在仿生表面研究方面取得重要进展

　　2016年4月7日，Nature在线发表了北京航空航天大学陈华伟教授、张德远教授和江雷研究员等的合作研究成果“Continuous directional water transport on the peristome surface of Nepenthes alata”（猪笼草口缘区表面液膜连续定向搬运机制）。该研究揭示了生物体表面结构无动力液膜搬运现象的原理，为机械表面/界面的仿生设计与生物制造奠定了理论与技术基础。论文连接：http://www.nature.com/nature/jou ... ll/nature17189.html

　　翼状猪笼草（学名：Nepenthes alata），又名红瓶猪笼草，是菲律宾特有的热带“食虫植物”，其口缘区在湿润环境下显现出优异的湿滑特性，昆虫很难驻足在口缘区，常会“失足”而滑落至捕虫笼内而被捕食（图1）。这一奇特生物现象吸引了科学家的兴趣，但前期研究大多集中在如何模仿猪笼草类叶片湿滑特征，尚未对其表面润湿特征进行揭示。

　　研究团队深入分析了猪笼草口缘区表面微观结构上的液膜铺展过程，首次发现液膜定向连续搬运的神奇现象，提出了梯度泰勒毛细升、闭口梯度泰勒毛细升理论计算模型，揭示了液膜定向连续搬运机理（图2），发展了传统泰勒毛细升理论。进一步研究了表面亲水、疏水特性对液膜定向搬运能力的影响规律，提出了基于楔形盲孔正向搬运、拱形边缘反向阻止的液膜定向连续搬运仿生机械表面/界面设计原理，基于生物复制成形方法实现了逼真形貌的转移制造。研究成果可应用于医疗器械、MEMS、航空航天等装备的表面/界面自润滑、抗磨损、防粘附等。

Continuous directional water transport on the peristome surface of Nepenthes alata
Huawei Chen,
Pengfei Zhang,
Liwen Zhang,
Hongliang Liu,
Ying Jiang,
Deyuan Zhang,
Zhiwu Han
& Lei Jiang

Nature 532, 85–89 (07 April 2016) doi:10.1038/nature17189 Received 18 February 2015 Accepted 25 January 2016 Published online 06 April 2016

Numerous natural systems contain surfaces or threads that enable directional water transport1, 2, 3, 4, 5, 6, 7. This behaviour is usually ascribed to hierarchical structural features at the microscale and nanoscale, with gradients in surface energy8, 9 and gradients in Laplace pressure10 thought to be the main driving forces. Here we study the prey-trapping pitcher organs of the carnivorous plant Nepenthes alata. We find that continuous, directional water transport occurs on the surface of the ‘peristome’—the rim of the pitcher—because of its multiscale structure, which optimizes and enhances capillary rise11, 12 in the transport direction, and prevents backflow by pinning in place any water front that is moving in the reverse direction. This results not only in unidirectional flow despite the absence of any surface-energy gradient, but also in a transport speed that is much higher than previously thought. We anticipate that the basic ‘design’ principles underlying this behaviour could be used to develop artificial fluid-transport systems with practical applications.

Subject terms: Biomaterials
Biological physics
Biosurfaces

古植物是化石的歌!

2016-4-13 05:04 PM