US 12,384,939 B1
Kirigami-inspired structures for smart adhesion
Michael Bartlett, Ames, IA (US); and Dohgyu Hwang, Ames, IA (US)
Assigned to Iowa State University Research Foundation, Inc., Ames, IA (US)
Filed by Iowa State University Research Foundation, Inc., Ames, IA (US)
Filed on Jan. 21, 2020, as Appl. No. 16/748,442.
Claims priority of provisional application 62/795,231, filed on Jan. 22, 2019.
Int. Cl. C09J 7/20 (2018.01); C09J 7/29 (2018.01)
CPC C09J 7/29 (2018.01) [C09J 7/203 (2018.01); C09J 2301/31 (2020.08)] 22 Claims
OG exemplary drawing
 
1. An adhesive film or sheet structure having a length, width, thickness, and opposite sides for releasable adhesion to target surfaces comprising:
a. spatially varied stiff and compliant regions formed in a continuous inextensible layer along a first direction with one or more interconnects between adjacent stiff regions; and
b. a mounting interface with adhesive characteristics along at least the spatially varied stiff regions on at least one side of the continuous inextensible layer adapted for releasable adhesion to target surfaces;
so that adhesion strength of the adhesive film or sheet structure and directional characteristics for release of the mounting interface of the adhesive film or sheet structure from a target surface along the first direction are enhanced by the formed spatially varied stiff and compliant regions in comparison to adhesive film or sheet structure without the formed spatially varied stiff and compliant regions.
 
20. An adhesive film or sheet product having reversible adhesive properties made by the process comprising:
a. fabricating in an inextensible sheet or film a kirigami-inspired continuous network of a series of closed portions separated by openings along an axis of the inextensible sheet or film, optionally including at least one interconnect bridging or framing a side of each opening between adjacent closed portions, the inextensible sheet or film being more inextensible than all other components of the adhesive sheet or film product; and
b. including, before or after the fabricating the kirigami-inspired continuous network, an exposed reversible adhesive mounting interface across at least the closed portions of at least one side of the inextensible sheet or film, wherein the inextensible sheet or film and the exposed reversible adhesive mounting interface have a substantially equal overall thickness along the adhesive film or sheet product;
to provide spatially controlled variation in bending strength at different locations along the axis of the adhesive film or sheet product for an anisotropic response to peeling along the axis.