Investigation of 2D polymer thin films in 3D structures involving Crumpling, Origami, Kirigami and Adhesion
Abstract
This dissertation delves into the fascinating world of thin films and their ability to transform into three-dimensional (3D) structures. One can simply crush a sheet of paper into a ball to make a 3D object a faster, yet more complex structure or by following a more organized folding technique (Origami) to create 3D objects with predictable structures. This dissertation mainly focuses on such 3D structures and introduces cuts (Kirigami) and adhesion to those 3D structures to understand more of their mechanical behavior.
The investigation of polymer crumple mechanics by introducing the Kirigami approach, and exploring how the sheet's topology influences crumpling, is discussed in this dissertation, which employs confocal microscopy, force experiments, and molecular dynamics simulations to investigate the effects of cutting on the behavior of crumpled sheets. The findings reveal that cutting does not significantly alter the compressive behavior; force scales according to a power law regardless of cuts, with only minor reductions in magnitudes.
The second chapter of this dissertation studies Origami-inspired adhesive capable of securely holding objects on a wall yet easily removable without damage, which should withstand significant forces when attached, and then swiftly transition to a low-adhesion state for removal. Bi-stability of the proposed Origami designs with different compliance to achieve noticeable switching ratios has been investigated. These devices demonstrate moderate switching ratios and scalability, offering the potential for arrayed applications through repetition of the Origami pattern.
Crumples combined with adhesion create stable 3D structures made from elastic thin sheets. The last chapter discusses the impact mitigation of such crumpling systems by observing sticky crumpled matter subjected to simple ball drop tests. These findings highlight the potential utility of sticky crumples as replacements for intricate engineered structures in protective layers.