Jens Bauer

Karlsruhe Institute of Technology | KIT · Institute of Nanotechnology

The strength of lightweight mechanical metamaterials, which aim to exploit material-strengthening size effects by their microscale lattice structure, has been limited by the resolution of three-dimensional lithography technologies and their restriction to mainly polymer resins. Here, we demonstrate that pyrolysis of polymeric microlattices can over...

In 1903 Alexander Graham Bell developed a design principle to generate lightweight, mechanically robust lattice structures based on triangular cells; this has since found broad application in lightweight design. Over one hundred years later, the same principle is being used in the fabrication of nanolattice materials, namely lattice structures comp...

Though beam-based lattices have dominated mechanical metamaterials for the past two decades, low structural efficiency limits their performance to fractions of the Hashin-Shtrikman and Suquet upper bounds, i.e. the theoretical stiffness and strength limits of any isotropic cellular topology, respectively. While plate-based designs are predicted to...

Failure of materials and structures is inherently linked to localized mechanisms, from shear banding in metals, to crack propagation in ceramics and collapse of space‐trusses after buckling of individual struts. In lightweight structures, localized deformation causes catastrophic failure, limiting their application to small strain regimes. To ensur...

Three-dimensional (3D) printing of silica glass is dominated by techniques that rely on traditional particle sintering. At the nanoscale, this limits their adoption within microsystem technology, which prevents technological breakthroughs. We introduce the sinterless, two-photon polymerization 3D printing of free-form fused silica nanostructures fr...

Architected metals and ceramics with nanoscale cellular designs, e.g., nanolattices, are currently subject of extensive investigation. By harnessing extreme material size effects, nanolattices demonstrated classically inaccessible properties at low density, with exceptional potential for superior lightweight materials. This study expands the concep...

Failure of materials and structures is the inevitable consequence of a catastrophic chain reaction of locally confined damage events. Breaking with this paradigm, in article number 2005647, Julian J. Rimoli, Lorenzo Valdevit, and co‐workers introduce a novel class of tensegrity metamaterials. By connecting isolated loops of compressive elements thr...

3D-printed nano-architected ceramic metamaterials currently emerge as a class of lightweight materials with exceptional strength and stiffness. However, their application is hampered by the lack of knowledge on their mechanical reliability. Characteristics like the fracture strength and their dependency on environmental conditions are unknown. We h...

Two-photon polymerization direct laser writing (TPP-DLW) is one of the most versatile technologies to additively manufacture complex parts with nanoscale resolution. However, the wide range of mechanical properties that results from the chosen combination of multiple process parameters imposes an obstacle to its widespread use. Here we introduce a...

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3D-printed nano-architected ceramic metamaterials currently emerge as a class of lightweight materials with exceptional strength and stiffness. However, their application is hampered by the lack of knowledge on their mechanical reliability. Characteristics like the fracture strength and their dependency on environmental conditions are unknown. We h...

In article number 1903834, Lorenzo Valdevit and co‐workers architect carbon nanospinodal material from a 170 nm‐thick shell of spinodal topology that exhibits exceptional energy absorption upon compression, while also being stiff, strong and lightweight. The topology is designed by solving the Cahn–Hilliard equation; the lattice is manufactured via...

Glassy carbon nanospinodals show non-catastrophic deformability up to 80% strain, enabling order of magnitude higher energy absorption capability than any reported nano-, micro- and macro-architected and monolithic material. At the same time, strength and stiffness are on par with the most advanced, yet brittle nanolattices, demonstrating true mult...

Ductile high-strength ceramics would be ideal for many structural applications; however, they have been neither demonstrated at dimensions much above the nanoscale nor shown to be manufacturable with application-relevant processes. Here, we present a robust route to additively manufacture ductile, ultrastrong silicon oxycarbide nanoceramics via two...

Nanolattices are promoted as next‐generation multifunctional high‐performance materials, but their mechanical response is limited to extreme strength yet brittleness, or extreme deformability but low strength and stiffness. Ideal impact protection systems require high‐stress plateaus over long deformation ranges to maximize energy absorption. Here...

Two‐photon polymerization direct laser writing (TPP‐DLW) is the most promising technology for additive manufacturing of geometrically complex parts with nanoscale features, and could dramatically accelerate the development of a wide range of engineering micro/nanosystems. However, a major obstacle to TPP‐DLW's widespread industrial adoption is the...

The mechanical response of cellular materials with spinodal topologies is numerically and experimentally investigated. Spinodal microstructures are generated by the numerical solution of the Cahn-Hilliard equation. Two different topologies are investigated: ‘solid models,’ where one of the two phases is modeled as a solid material and the remaining...

By designing advantageous cellular geometries and combining the material size effects at the nanometer scale, lightweight hybrid microarchitectured materials with tailored structural properties are achieved. Prior studies reported the mechanical properties of high strength cellular ceramic composites, obtained by atomic layer deposition. However, f...

Lattice materials are strong yet light. Miniaturizing the pattern size to the micro-scale allows exploiting mechanical size effects. So far, the impact of the lattice size on the strength has not been studied systematically and mechanical characterization has been focused on compression tests only. Here, the strength of polymer–alumina core–shell c...

Cellular materials with specific three-dimensional microarchitectures achieve outstanding strength-to-weight ratios due to the mechanical size effect and their optimized architecture. By applying 3D direct laser writing and different coating techniques the materials can be fabricated as polymer nanocomposites. So far, mainly coating materials and t...

Designing materials with exceptional combinations of properties at low weight is a continuous goal in many industries. Cellular (i.e., porous) materials with one or more phases topologically organized in a precisely designed configuration (often denoted as architected materials, or metamaterials) are excellent candidates to reach combinations of pr...

The search for light yet strong materials recently benefitted from novel high resolution 3D-printing technologies, which allow for fabricating lightweight porous materials with optimally designed micro-topologies. Architectural design improves mechanical properties significantly compared to stochastic porosity, as in foams. Miniaturization of the a...

Significance It has been a long-standing effort to create materials with low density but high strength. Technical foams are very light, but compared with bulk materials, their strength is quite low because of their random structure. Natural lightweight materials, such as bone, are cellular solids with optimized architecture. They are structured hie...