Buckled Structures: Fabrication and Applications in Wearable Electronics

Abstract

Wearable electronics have attracted a tremendous amount of attention due to their many potential applications, such as personalized health monitoring, motion detection, and smart clothing, where electronic devices must conformably form contacts with curvilinear surfaces and undergo large deformations. Structural design and material selection have been the key factors for the development of wearable electronics in the recent decades. As one of the most widely used geometries, buckling structures endow high stretchability, high mechanical durability, and comfortable contact for human–machine interaction via wearable devices. In addition, buckling structures that are derived from natural biosurfaces have high potential for use in cost‐effective and high‐grade wearable electronics. This review provides fundamental insights into buckling fabrication and discusses recent advancements for practical applications of buckled electronics, such as interconnects, sensors, transistors, energy storage, and conversion devices. In addition to the incorporation of desired functions, the simple and consecutive manipulation and advanced structural design of the buckled structures are discussed, which are important for advancing the field of wearable electronics. The remaining challenges and future perspectives for buckled electronics are briefly discussed in the final section.

Nanomaterials Innovation

“…[20] Nanogenerators show promising applications in artificial intelligence, self-powered sensing systems, wearable electronics, artificial neuromorphic system and other fields in the future. [21] In these future applications, structural design and material selection have been the key factors. Innovative nanomaterials with superior electrical and chemical properties would be good foundations.…”

“…Nanotechnology has affected both material optimization and structural designs in thermoelectric nanogenerators . Nanogenerators show promising applications in artificial intelligence, self‐powered sensing systems, wearable electronics, artificial neuromorphic system and other fields in the future . In these future applications, structural design and material selection have been the key factors.…”

Long wavy copper stretchable interconnects fabricated by continuous microcorrugation process for wearable applications

“…F I G U R E 1 Proposed stretchable interconnects connected by wavy Cu interconnects and fabrication by microcorrugation process Several fabrication methods of stretchable interconnects including stretchable conductive inks, nanostructured metal particles, liquid metals, buckled structures, two-or three-dimensional (3D) spring structures have been previously reported. 3,8,9 First, stretchable inks have been developed by mixing silver flake, [10][11][12][13] carbon nanotube (CNT), 14 or other conductive materials 1,8,9 with thermoplastic polyurethane resin (TPU) or fluorine rubber. In addition, the mixture of several conductive materials including CNT and silver particles are embedded in rubber for higher stretchability and conductivity.…”

“…Since the cracked film can deflect and twist out of plane, tribranched microcracks of thin metal film can sustain up to 30% stretch but the length of the microcrack electrode is limited up to 20 cm which is determined by the size of vacuum chamber of metal sputter. 8,9,21,22 Fifth, a horizontal spring-like structure of metal interconnects has been constructed by lithography and etching processes. [23][24][25][26][27][28][29] These horseshoe-patterned interconnects have the advantage of high conductivity and stretchability, but require large surface areas for one electrode.…”

Hierarchical 3D Patterns with Dynamic Wrinkles Produced by a Photocontrolled Diels–Alder Reaction on the Surface

“…This strategy, based on a photocontrolled D-A reaction, provides an important and robust alternative for fabricating 3D patterned surfaces with dynamic topographies.Hierarchically patterned surfaces are widely found in natural and man-made materials and biological skins, in which structures with a topographic hierarchy across multiple scales can impart intriguing and outstanding properties to the surface due to the synergistic effects of hierarchical structures. [1][2][3][4][5][6][7] Inspired by these hierarchical patterns, researchers have engineered hierarchical surfaces for various applications ranging from wetting control [8] and structural colors [9] to tissue scaffolds [10] using diverse patterning approaches, including typicalThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.…”