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

Abstract

Assembly of 3D micro/nanostructures in advanced functional materials has important implications across broad areas of technology. Existing approaches are compatible, however, only with narrow classes of materials and/or 3D geometries. This paper introduces ideas for a form of Kirigami that allows precise, mechanically driven assembly of 3D mesostructures of diverse materials from 2D micro/nanomembranes with strategically designed geometries and patterns of cuts. Theoretical and experimental studies demonstrate applicability of the methods across length scales from macro to nano, in materials ranging from monocrystalline silicon to plastic, with levels of topographical complexity that significantly exceed those that can be achieved using other approaches. A broad set of examples includes 3D silicon mesostructures and hybrid nanomembrane-nanoribbon systems, including heterogeneous combinations with polymers and metals, with critical dimensions that range from 100 nm to 30 mm. A 3D mechanically tunable optical transmission window provides an application example of this Kirigami process, enabled by theoretically guided design.Kirigami | three-dimensional assembly | buckling | membranes T hree-dimensional micro/nanostructures are of growing interest (1-10), motivated by their increasingly widespread applications in biomedical devices (11-13), energy storage systems (14-19), photonics and optoelectronics (20-24), microelectromechanical systems (MEMS) (25-27), metamaterials (21,(28)(29)(30)(31)(32), and electronics (33-35). Of the many methods for fabricating such structures, few are compatible with the highest-performance classes of electronic materials, such as monocrystalline inorganic semiconductors, and only a subset of these can operate at high speeds, across length scales, from centimeters to nanometers. For example, although approaches (36-39) that rely on self-actuating materials for programmable shape changes provide access to a wide range of 3D geometries, they apply only to certain types of materials [e.g., gels (36, 37), liquid crystal elastomers (39), and shape memory alloys (38)], generally not directly relevant to high-quality electronics, optoelectronics, or photonics. 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, 40-44). 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. The concepts of Kirigami, an ancient aesthetic pursuit, involve strategically configured arrays of cuts to gui...

Exploiting Microstructural Instabilities in Solids and Structures: From Metamaterials to Structural Transitions

“…14(a)) and 2D arrays of rotating units [190] result in large extension and a range of nonlinear mechanical responses. Finally, mechanical instabilities in flat thin sheets with an embedded array of cuts subjected to uniaxial tension can result in out-of-plane deformation and the formation of 3D architectures [191,192] (see Fig. 14(b)), providing opportunities for the design of highly stretchable devices [193][194][195][196][197][198] and morphable structures [191,199,200].…”

Transmission gaps from corrugations

“…These results can provide an access to design a curvature-tunable filter. With the advent and development of nanostructure technology, a variety of nanostructures with complex geometries were successfully fabricated, such as corrugated semiconductor films [1][2][3][4][5][6] , rolled-up nanotubes [7][8][9][10][11][12] , Möbius stripes [13][14][15] , peanut-shaped C 60 polymers [16][17][18][19][20] . These successes in experiment found the basis of the emerging nanoelectronics.…”

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). …”