Three-dimensional mesostructures as high-temperature growth templates, electronic cellular scaffolds, and self-propelled microrobots

Abstract

SignificanceExploiting advanced 3D designs in micro/nanomanufacturing inspires potential applications in various fields including biomedical engineering, metamaterials, electronics, electromechanical components, and many others. The results presented here provide enabling concepts in an area of broad, current interest to the materials community––strategies for forming sophisticated 3D micro/nanostructures and means for using them in guiding the growth of synthetic materials and biological systems. These ideas offer qualitatively differentiated capabilities compared with those available from more traditional methodologies in 3D printing, multiphoton lithography, and stress-induced bending––the result enables access to both active and passive 3D mesostructures in state-of-the-art materials, as freestanding systems or integrated with nearly any type of supporting substrate.

Processing‐Dependent Microstructure of AgCl–CsAgCl2 Eutectic Photonic Crystals

“…However, this alignment can be attributed to the orientation of the solidification direction not coinciding with the draw direction . The orientation of the eutectic solidification front is determined by the details of the heat transfer in the eutectic material and the substrate for the given thermal condition, as previously demonstrated by simulations . Heat transfer simulations were performed using COMSOL to map the temperature profile in the eutectic material during directional solidification (see the Experimental Section for details).…”

“…Among possible motifs provided by eutectic solidification, the regular microstructures of lamellar and rod eutectics have direct resemblance to 1D and 2D photonic crystals, respectively, where the phase‐separated components provide the required contrast in the refractive index to exhibit a unique optical response . The components of eutectic materials can be chosen from metals, semiconductors, polymers, organics, ceramics, or salts; thus providing metal, dielectric, or even metallodielectric composites with which to synthesize (or to act as templates for) photonic crystals . Recent examples from literature have demonstrated the formation of photonic crystals and other optically interesting structures (for applications like diffraction gratings, phase‐separated scintillators with light guiding, and absorption‐induced transparency) in directionally solidified chloride‐based molten salt eutectics, such as AgCl‐KCl, NaCl‐CsI, CuI‐KCl, and KCl‐LiF .…”

“…The components of eutectic materials can be chosen from metals, semiconductors, polymers, organics, ceramics, or salts; thus providing metal, dielectric, or even metallodielectric composites with which to synthesize (or to act as templates for) photonic crystals . Recent examples from literature have demonstrated the formation of photonic crystals and other optically interesting structures (for applications like diffraction gratings, phase‐separated scintillators with light guiding, and absorption‐induced transparency) in directionally solidified chloride‐based molten salt eutectics, such as AgCl‐KCl, NaCl‐CsI, CuI‐KCl, and KCl‐LiF . The eutectic solidification‐based synthesis route is particularly simple if the eutectics have a low melting temperature and low surface energy, are devoid of any corroding components, like fluorides, and do not require controlled atmospheres during fabrication.…”

Inorganic Stimuli‐Responsive Nanomembranes for Small‐Scale Actuators and Robots

“…Copyright 2010, Royal Society of Chemistry; b) FEM images of 3D swimmer suspended by human hairs. Reproduced with permission . Copyright 2017, National Academy of Science; c) An SEM image of a remotely actuated untethered microgripper.…”

Postbuckling analyses of frame mesostructures consisting of straight ribbons for mechanically guided three-dimensional assembly

“…Three-dimensional (3D) mesostructures with different geometrical topologies, feature sizes and material compositions have been intensively investigated in recent years [1][2][3], showing their promising potentials in various classes of micro/nanotechnologies, such as microelectromechanical systems [4,5], energy storage systems [6,7], biomedical devices [8,9], photonics and optoelectronics [10,11], micro-motors/robotics [12,13], flexible electronics [14][15][16][17] and many others. Diverse manufacturing techniques were developed for this purpose, including, for example, additive manufacturing [18][19][20], microcontact printing [21,22], volumetric optical exposures [23,24], self-rolling/folding induced by residual stresses [25,26] and mechanically guided 3D assembly [27][28][29][30][31].…”