Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2020 Dec 18;125(25):254503. doi: 10.1103/PhysRevLett.125.254503.
We report polymorphic self-assembly of hair arranged in hollow bundles driven by capillarity, hydrodynamics, and elasticity. Bundles emerging from a liquid bath shrink but remain hollow at slow drainage due to the negative pressure of the menisci trapped between the hairs. The timescale allows the collective stiffening of the fibers to resist closure. At fast drainage, the bundles fully close before the liquid can drain through the hair. A liquid column trapped in the hole closes the bundle while the lubricated hairs still behave softly. Scaling laws predict this reversible hair polymorphism.
我们报告了由毛发生成的空心束的多晶自组装，其驱动力包括毛细作用、流体力学和弹性。从液体浴中伸出的束在缓慢排水时会收缩，但由于被困在毛发之间的弯月面的负压，仍然保持空心。这个时间尺度允许纤维的集体变硬以抵抗闭合。在快速排水时，束在液体可以通过毛发排出之前完全关闭。被困在孔中的液体柱关闭束，而润滑的毛发仍然表现出柔软的特性。标度定律预测了这种可逆的毛发多态性。
