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Harnessing Tunable Scanning Probe Techniques to Measure Shear Enhanced Adhesion of Gecko-Inspired Fibrillar Arrays
journal contribution
posted on 2015-02-04, 00:00 authored by Yasong Li, James
H.-W. Zhou, Cheng Zhang, Carlo Menon, Byron D. GatesThe hierarchical arrays of mesoscale
to nanoscale fibrillar structures
on a gecko’s foot enable the animal to climb surfaces of varying
roughness. Adhesion force between the fibrillar structures and various
surfaces is maximized after the gecko drags its foot in one direction,
which has also been demonstrated to improve the adhesion forces of
artificial fibrillar arrays. Essential conditions that influence the
magnitude of these interactions include the lateral distance traveled
and velocity between the contacting surfaces, as well as the velocity
at which the two surfaces are subsequently separated. These parameters
have, however, not been systematically investigated to assess the
adhesion properties of artificial adhesives. We introduce a systematic
study that investigates these conditions using a scanning probe microscope
to measure the adhesion forces of artificial adhesives through a process
that mimics the mechanism by which a gecko climbs. The measured adhesion
response was different for arrays of shorter and longer fibrils. These
results from 9000 independent measurements also provide further insight
into the dynamics of the interactions between fibrillar arrays and
contacting surfaces. These studies establish scanning probe microscopy
techniques as a versatile approach for measuring a variety of adhesion
properties of artificial fibrillar adhesives.