I really like it, very convincing~~
So many interesting things exist in the world. I love biology research.
I saw this paper from a blog
花瓣上带着水珠，这是玫瑰的经典形象。即使塑料假花上，人们也会做逼真的水珠。这种斥水性很常见，但玫瑰花瓣有独特之处。即使翻过来，花上的水珠也不会掉落。不像荷叶之类，稍有动静，失掉平衡，水珠就滑下去了。
水会滑下去，因为微观表面粗糙、多刺，刺尖上有蜡。水只和一小部分表面接触，那就是蜡。清华大学的 Lin Feng 等人发现，玫瑰花瓣有类似的表面结构，但刺间的低洼比较宽，平缓，而且没有蜡。那些刺让水保持球形。水渗入低洼处，水珠因此被“粘”住了。
（示意图：左边是玫瑰花瓣，右边是荷叶。）花瓣的这种特性和具体材料的化学特性无关，只和表面的物理结构有关。
Langmuir. 2008 Apr 15;24(8):4114-9.
Petal effect: a superhydrophobic state with high adhesive force.
Feng L, Zhang Y, Xi J, Zhu Y, Wang N, Xia F, Jiang L.Department of Chemistry, Tsinghua University, Beijing, P. R. China. fl@mail.tsinghua.edu.cn
Hierarchical micropapillae and nanofolds are known to exist on the petals' surfaces of red roses. These micro- and nanostructures provide a sufficient roughness for superhydrophobicity and yet at the same time a high adhesive force with water. A water droplet on the surface of the petal appears spherical in shape, which cannot roll off even when the petal is turned upside down. We define this phenomenon as the "petal effect" as compared with the popular "lotus effect". Artificial fabrication of biomimic polymer films, with well-defined nanoembossed structures obtained by duplicating the petal's surface, indicates that the superhydrophobic surface and the adhesive petal are in Cassie impregnating wetting state.
Du, Macara, 2004 cell: "HeLa cells were synchronized by double thymidine (2 mg ml-1) block."