Tawfick team finds new hair-bundle properties


Sam TawfickMechSE associate professor Sam Tawfick, with a team including postdoc Jonghyun Ha, MechSE graduate student Yun Seong Kim, and MechSE undergraduate students Ryan Siu and Kaiying Jiang, has published new research in Physical Review Letters.

The title is Hydrodynamic Elastocapillary Morphing of Hair Bundles. The research is funded by the Air Force Office of Scientific Research and the National Science Foundation.

Abstract: 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.

Read full publication on Physical Review Letters.