Assembly of micro/nanomaterials into complex, three-dimensional architectures by compressive buckling

Abstract

Complex three-dimensional (3D) structures in biology (e.g., cytoskeletal webs, neural circuits, and vasculature networks) form naturally to provide essential functions in even the most basic forms of life. Compelling opportunities exist for analogous 3D architectures in human-made devices, but design options are constrained by existing capabilities in materials growth and assembly. We report routes to previously inaccessible classes of 3D constructs in advanced materials, including device-grade silicon. The schemes involve geometric transformation of 2D micro/nanostructures into extended 3D layouts by compressive buckling. Demonstrations include experimental and theoretical studies of more than 40 representative geometries, from single and multiple helices, toroids, and conical spirals to structures that resemble spherical baskets, cuboid cages, starbursts, flowers, scaffolds, fences, and frameworks, each with single- and/or multiple-level configurations.

Rational design of reconfigurable prismatic architected materials

“…Although additional local deformation arises from the finite size of the flexible hinges, the 3D printed structures exhibit the same deformation modes predicted by our numerical analysis and observed in the cardboard prototypes. As such, recent advances in fabrication, including projection micro-stereolithography, 7 two-photon lithography 8,32,33 and 'pop-up' strategies, [34][35][36][37][38][39][40] open exciting opportunities for miniaturization of the proposed architectures. All together, our strategy enables the design of a new class of reconfigurable systems across a wide range of length scales that is waiting to be explored.…”

Thermal Release Transfer Printing for Stretchable Conformal Bioelectronics

“…In this technique, dynamic control of the interfacial adhesion between the stamp and the object to be transferred plays a crucial role in completing successful transfer printing. As shown in Table 1 , several strategies for adhesion control of transfer printing technique have been proposed and applied in the stretchable bioelectronics fabrication (e.g., complex 3D mesostructures,14, 15, 16, 17, 18, 19, 20 wireless biomedical devices,17, 21, 22, 23, 24, 25, 26, 27 and epidermal sensor systems23, 28, 29, 30, 31, 32, 33, 34, 35). …”

A mechanically driven form of Kirigami as a route to 3D mesostructures in micro/nanomembranes

“…Techniques that exploit bending/folding of thin plates via the action of residual stresses or capillary effects are, by contrast, naturally compatible with these modern planar technologies, but they are currently most well developed only for certain classes of hollow polyhedral or cylindrical geometries (1,10,(40)(41)(42)(43)(44). Other approaches (45,46) rely on compressive buckling in narrow ribbons (i.e., structures with lateral aspect ratios of >5:1) or filaments to yield complex 3D structures, but of primary utility in opennetwork mesh type layouts. Attempts to apply this type of scheme to sheets/membranes (i.e., structures with lateral aspect ratios of <5:1) lead to "kink-induced" stress concentrations that cause mechanical fracture.…”

“…Compressive forces imparted in the plane at selected points (anchors; red, in SI Appendix, Fig. S2) deform the systems into engineered 3D configurations via lateral buckling (50), using a concept similar to the one exploited in 3D filamentary networks (46). The left frame of by narrow joints.…”

“…1, these Kirigami concepts can naturally include ribbon-shaped precursors (46), to yield complex 3D structures, including those with multiple levels of buckling. Fig.…”