Self Forming Spatular Structures

As a model for self-forming spatular structures we have fabricated model core-shell fibrils by coating an aluminum wire with (poly)dimethylsiloxane.

( a) Optical micrograph of a terminal shell fabricated by a coating an aluminum wire by PDMS and partially etching the wire. (b) Scanning electron micrograph of a coated, partially etched, and trimmed sample with shell thickness of about 25 microns.

 

Schematic drawing of set-up to test adhesion under shear. The fibril is preloaded in the vertical direction upto a fixed displacement before being dragged horizontally.

 

Initial contact of the shell with the substrate increases with increasing displacement.

 

 

Shear force increases with increasing initial displacement. Dragging is accomodated by stick-slip.

see movie

(Matt Havener, Vince Sica, T. Tang)