Comparison of smooth and hairy attachment pads in insects: friction, adhesion and mechanisms for direction-dependence

James M. R. Bullock, Patrick Drechsler and Walter Federle

Purpose:

Biomemitic technologies provide a valuable opportunity to borrow methods and uses from many years of optimization through evolution.  The aim of this study was to compare the performance of smooth and fibrillar systems in insects to clarify the mechanisms of attachment and removal.  This includes determining how smooth versus hairy attachment influences frictional performance, the importance of fluid pad secretion and its role in adhesion, and if there is any mechanism for direction dependence of attachment.

 

Methods:

A force transducer was used to measure friction forces of the insects feet which employed foil strain gauges and a three dimensional DC driven stage. Optical images were obtained using a camera and LabView and Matlab were used for data analysis from the home built system.

 

Key Findings:

1. Direction dependence of adhesion was observed with dramatically decreased adhesion in the distal direction but not the proximal.

2. No load dependence was observed for friction, contact area, or shear stress

3. Smooth/Hairy comparison of attachment found nearly 2x adhesion forces for the hairy system over the smooth

4.  Fluid pad secretion was quickly depleted from the contact zone and provide hydrophobic contacts to promote adhesion.

Diamond FED diodes

Final Paper    Final Paper

Final Presentation     Final Presention

Therapeutic Nanodevices: Drug Delivery

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December 18, 2008

Functionalized Nanomaterials for Medical Applications

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