题 目：Mechanics-guided Deterministic 3D Assembly （基于确定性力学导向的3维组装技术）

报 告 人：黄永刚 院士 （Northwestern University）

时 间：2018年7月12日（周四）14：30

地 点：延长校区应用数学和力学所东会议室

摘 要：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 [1]. The schemes involve geometric transformation of 2D micro/nanostructures into extended 3D layouts by compressive buckling. Designs inspired by kirigami/origami [2,3] and/or releasable multilayers [4] enable the formation of mesostructures with a broad variety of 3D geometries, either with hollow or dense distributions. Demonstrations include experimental and theoretical studies of more than 100 representative geometries, from single and multiple helices, toroids, and conical spirals to structures that resemble spherical baskets, cars, houses, cuboid cages, starbursts, flowers, scaffolds, each with single- and/or multiple-level configurations. Morphable 3D mesostructures whoese geometries can be elastically altered can be further achieved via nonlinear mechanical buckling, by deforming the elastomer platforms in different time sequences [5]. We further introduce concepts in physical transfer, patterned photopolymerization and non-linear plasticity to enable integration of 3D mesostructures onto nearly any class of substrate, with additional capabilities in access to fully or partially free-standing forms, all via mechanisms quantitatively described by theoretical modeling [6]. Compatibility with the well-established technologies available in semiconductor industries suggests a broad range of application opportunities [7]. Illustrations of these ideas include their use in building 3D structures as radio frequency devices for adaptive electromagnetic properties [5], as open-architecture electronic scaffolds for formation of dorsal root ganglion (DRG) neural networks [6], as ultra-stretchable interconnects for soft electronics [8] and as catalyst supports for propulsive systems in 3D micro-swimmers with geometrically controlled dynamics [6].

References

[1] Xu et al., 2015. Science 347, 154-159.

[2] Zhang et al., 2015. PNAS 112, 11757-11764.

[3] Yan et al., 2016. Advanced Functional Materials 26, 2629-2639.

[4] Yan et al., 2016. Science Advances 2, e1601014.

[5] Fu et al., 2018. Nature Materials 17, 268-276.

[6] Yan et al., 2017. PNAS 114, E9455-E9464.

[7] Zhang et al., 2017. Nature Reviews Materials 2, 17019.

[8] Jang et al., 2017. Nature Communications 8, 15894.