Evolutionary
Biomaterials Group
Max-Planck Inst for Metals Research, Stuttgart
Structure
and properties of biological hairy attachment devices for
biomimetics.
Stanislav N. Gorb
Abstract: Many animals bear leg attachment pads with an
excellent ability to adhere
to a smooth surface as well as to a variety of natural surfaces with
rough
profiles. There are two alternative designs of such systems: smooth and
hairy. The smooth systems consist of soft deformable structures with a
relatively smooth surface. Pads of geckos, flies, beetles, and spiders
are
covered by relatively long, deformable setae which, due to individual
bending, increase the number of contacting points with the surface. Most
recent data on hairy systems demonstrated their excellent adhesion and
high defect tolerance of contact. The size of single points gets smaller
and their density higher as the body mass increases. We provided the
first
experimental evidence of adhesion enhancement by division of contact
area.
A patterned surface, made out of polyvinylsiloxane (PVS), has
significantly higher tenacity on a glass surface than a smooth sample
made
out of the same material. This effect is even more pronounced on curved
substrata. An additional advantage of patterned surfaces is the
reliability of contact on various surface profiles and the increased
tolerance to defects of individual contacts.