Piercing an interface with a brush: collaborative stiffening

Abstract

The hairs of a painting brush withdrawn from a wetting liquid self-assemble into clumps whose sizes rely on a balance between liquid surface tension and hairs bending rigidity. Here we study the situation of an immersed carpet in an evaporating liquid bath : the free extremities of the hairs are forced to pierce the liquid interface. The compressive capillary force on the tip of flexible hairs leads to buckling and collapse. However we find that the spontaneous association of hairs into stronger bundles may allow them to resist capillary buckling. We explore in detail the different structures obtained and compare them with similar patterns observed in micro-structured surfaces such as carbon nanotubes "forests".

9 pages, 6 figures

References in corpus (3)

• Capillary origami: spontaneous wrapping of a droplet with an elastic sheet
• Kinks, rings, and rackets in filamentous structures
• Contact angle measurements on superhydrophobic Carbon Nanotube Forests : effect of fluid pressure

Cited by in corpus (5)

• Soft wetting and the Shuttleworth effect, at the crossroads between thermodynamics and mechanics
• A fluid-mechanical model of elastocapillary coalescence
• Deformation of a free interface pierced by a tilted cylinder
• Capillarity of soft amorphous solids: a microscopic model for surface stress
• Elastocapillary instability under partial wetting conditions: bending versus buckling