Architectural tunability of mechanical metamaterials in the nanometer range

Abstract

Mechanical metamaterials can exhibit extraordinary mechanical properties due to a specific architecture rather than the base material. When the structural dimensions reach the sub-micrometer range, such micro- and nanolattices may also benefit from size-affected mechanical properties. However, well-defined geometric adjustments on this length scale are limited by the resolution limits of the underlying manufacturing technology. Here, we used a 3D direct laser writing (3D-DLW) process with integrated laser power variation to fabricate polymeric microlattices, which were then pyrolized to obtain glassy carbon structures. The laser power was varied by a quadratic function along the beams from one node to another over the length of a unit cell, thus enabling geometric adjustments in the range of a few nanometers. Rounded and notch-like joints were realized by increased and reduced laser power at the nodes, respectively. Furthermore, the beam cross section was varied along the beam length, thereby creating convex or concave beam shapes. A laser power variation opens up new design possibilities for micro- and nanolattices in the sub-micrometer range by overcoming process related limitations.

In Situ Pyrolysis of 3D Printed Building Blocks for Functional Nanoscale Metamaterials

“…[29,30] We choose a series of microstrut structures with 10 μm length and use springs and disc-shape pedestals as decoupling supports, as suggested in the literature. [6,31] Their cross sections were designed with varying squares with lateral dimensions of 1 × 1, 2 × 2, 3 × 3, and 4 × 4 μm and are referred to in the following as G1, G2, G3, and G4, respectively. A cross-sectional analysis of the as-printed microstruts reveals an elongation in Z-direction, see Figure S1 (Supporting Information).…”

3D‐Printed Inherently Porous Structures with Tetrahedral Lattice Architecture: Experimental and Computational Study of Their Mechanical Behavior

“…[19][20][21][22] The stiffness of such printed structures, for example, can be manipulated by varying the dimensions of the struts and the number of cells [23] but also through variation of the strut and node geometries by changing the printing parameters. [24] Therefore, developing new latticebased architectures based on the precisely evaluated mechanical parameters of the base materials is envisioned.…”