Patent ID: 7700173

Claim:
A dry fibrillar microstructure that adheres to and is reapplicable to a surface, and that comprises (a) a substrate, and (b) a plurality of fibrils attached to the substrate, wherein the minimum distance between the surface of a first fibril and the surface of a second adjacent fibril, at the plane of attachment of the fibrils to the substrate, is a distance 2w where w is determined from Equation IV; wherein each of the first and second fibrils has a neutral axis, passing through the centroid of the cross-sectional area of the fibril, that has an orientation with the plane of the substrate, at the point of intersection of the axis with the plane of the substrate, in the range of greater than 75° to about 90°; wherein Equation IV is w >( g 2 *L 2 /4 a )*(2γ/3 Ea ) 1/2 ; and wherein E is the Young's modulus of the material of the first or second fibril as determined by ASTM D412-87, a is one-half of the characteristic width of the first or second fibril, L is the length of the first or second fibril, γ is the surface energy of the material of the first or second fibril as determined by ASTM D724-99, g is a dimensionless constant having a value in the range of about 0.05 to about 5.0, and * indicates multiplication.