SUBJECT: Ph.D. Proposal Presentation
BY: Jaekang Kim
TIME: Tuesday, April 23, 2019, 11:00 a.m.
PLACE: MRDC Building, 4211
TITLE: Wall-Shaped Hierarchical Microstructure for Gecko-Like Attachment
COMMITTEE: Dr. Michael Varenberg, Chair (ME)
Dr. Itzhak Green (ME)
Dr. Jeffrey Streator (ME)
Dr. David Hu (ME)
Dr. Daniel Goldman (Physics)


Temporary biological attachment systems have long intrigued scientists and engineers because the animals that have these systems are capable of climbing walls and even walking on ceilings irrespective of their surface properties. Recently, researchers have started to engineer dry adhesives inspired by the systems involving thin-film-based contact elements. Pillar-, mushroom-, wedge- and flap-shaped structures have been suggested and studied under various conditions. However, unlike prototype biological spatulate contact elements, which show a non-sticky default state, strong shear-induced attachment, and insensitivity to surface conditions, the current artificial microstructured adhesives are deficient in these abilities. As an alternative to the existing bio-inspired dry adhesives, a wall-shaped hierarchical microstructure has been suggested, and it shows great potential for being a true “gecko-like” attachment surface. However, it is still unclear how loading, and surface and environmental conditions affect the performance of this microstructure. It is also evident that its current laser-based manufacture can be considered impractical. To this end, the objective of this work is to study the attachment performance of wall-shaped adhesive microstructures, and to explore the possibility to manufacture them in a different way. The effects of pulling angle, preliminary displacement and counterface roughness have been investigated in the frame of preliminary work. To complete this study, the effects of surface free energy, material gradient, cyclic loading, and surface contamination along with a drawing-based manufacturing technique will be tested. This work will serve as the scientific and engineering foundation for the design of clean, easily detachable and simple bio-inspired grippers that may revolutionize use of reversible attachment.