For centuries, the ability of gecko lizards to climb any vertical surface or hang from ceilings with one toe has generated considerable interest. It has recently been discovered that the driving force for holding a gecko on a surface comes from its remarkable feet and toes, which are covered with countless aligned microscopic elastic hairs splitting into spatulae to take advantage of the strong van der Waals forces. This finding has prompted many researchers to use synthetic microarrays to mimic gecko feet. Recent work has indicated that aligned carbon nanotubes sticking out of substrate surfaces showed strong nanometer-scale adhesion forces.
Liming Dai and Liangti Qu, researchers at the University of Dayton (Dayton, OH), have demonstrated that a 4 × 4 mm vertically aligned single-walled-carbon-nanotube array can support a 500 g weight when dry adhered to a vertical glass surface. Further research on the carbon-nanotube gecko feet could lead to photosensitive or optoelectronically active dry adhesives attractive for diverse potential applications, ranging from smart packaging to advanced optoelectronic integration. Contact Liming Dai at [email protected].