Showing posts with label Metamaterials. Show all posts
Showing posts with label Metamaterials. Show all posts

Friday, August 11, 2017

A new featherweight, flame-resistant and super-elastic metamaterial from Purdue Uniuversity

Purdue University reports: WEST LAFAYETTE, Ind. — A new featherweight, flame-resistant and super-elastic metamaterial has been shown to combine high strength with electrical conductivity and thermal insulation, suggesting potential applications from buildings to aerospace.

A new composite material combines ultra-lightweight with flame-resistance, super-elasticity and other attributes that could make it ideal for various applications. Here, the material is viewed with a scanning electron microscope, while its flame resistance is put to the test. (Purdue University photo)

[From the abstract, Adv. Mater., DOI: 10.1002/adma.201605506] "A ceramic/graphene metamaterial (GCM) with microstructure-derived superelasticity and structural robustness is achieved by designing hierarchical honeycomb microstructures, which are composited with two brittle constituents (graphene and ceramic) assembled in multi-nanolayer cellular walls. Attributed to the designed microstructure, well-interconnected scaffolds, chemically bonded interface, and coupled strengthening effect between the graphene framework and the nanolayers of the Al2O3 ceramic (NAC), the GCM demonstrates a sequence of multifunctional properties simultaneously that have not been reported for ceramics and ceramics–matrix–composite structures, such as flyweight density, 80% reversible compressibility, high fatigue resistance, high electrical conductivity, and excellent thermal-insulation/flame-retardant performance simultaneously."
Findings were detailed in a research paper published on May 29 in the journal Advanced Materials. The paper was a collaboration between Purdue, Lanzhou University and the Harbin Institute of Technology, both in China, and the U.S. Air Force Research Laboratory. A research highlight about the work appeared in the journal Nature Research Materials and is available at A YouTube video (below) about the work is available at

The ALD process of the nanolayer Al2O3 ceramic (NAC) were performed in an Utratech Fiji F200 (now Veeco CNT) ALD system at 250 °C using trimethylaluminum (TMA) and H2O.

Tuesday, June 20, 2017

Light, Superelastic, Electrically Conductive, and Flame-Retardant Graphene / ALD Ceramic Metamaterial

Researcher from Lanzhou University (China) and Purdue University (USA) has developed a new ceramic/graphene wonder metamaterial (GCM) with microstructure-derived superelasticity and structural robustness is achieved by designing hierarchical honeycomb microstructures

The GCM is composited by two brittle constituents (graphene and ceramic) assembled in multi-nanolayer cellular walls. The GCM demonstrates a sequence of multifunctional properties simultaneously that have not been reported for ceramics and ceramics–matrix–composite structures, such as: 
  • flyweight density
  • 80% reversible compressibility
  • high fatigue resistance
  • high electrical conductivity
  • excellent thermal-insulation/flame-retardant performance simultaneously. 

All details can be find in the Advanced Materials publication below. According to the suppoirting information the Al2O3 ceramic depositions were performed in an Utratech Fiji F200 ALD system (pictured above) at 250 C using trimethylaluminum (TMA) and H2O as the aluminum and oxygen source, respectively.

Flyweight, Superelastic, Electrically Conductive, and Flame-Retardant 3D Multi-Nanolayer Graphene/Ceramic Metamaterial
Qiangqiang Zhang et al
Adv. Mater., DOI: 10.1002/adma.201605506

Sunday, December 6, 2015

Ultralight shape-recovering plate mechanical ALD metamaterials

Here is an Ultracool ALD application for creating Ultralight shape-recovering plate mechanical  metamaterials from University of Pennsylvania. Check out the paper and the Youtube video below. 

Sequential images of a structure with the ALD layer thickness of ~25 nm inside an FIB while being manipulated using a micromanipulator. (Nature Communications 6, Article number:10019 doi:10.1038/ncomms1001)

All details on the fabrication method can be found in the supplementary information document with free access:

And the paper itself is OPEN ACCESS !

Fabrication method of the periodic three-dimensional architecture of the mechanical metamaterial as described in the supplementary information document (Nature Communications 6, Article number:10019 doi:10.1038/ncomms1001)

Ultralight shape-recovering plate mechanical metamaterials

Keivan Davami, Lin Zhao, Eric Lu, John Cortes, Chen Lin, Drew E. Lilley, Prashant K. Purohit & Igor Bargatin

Nature Communications 6, Article number:10019 doi:10.1038/ncomms10019 Published 03 December 2015 

Unusual mechanical properties of mechanical metamaterials are determined by their carefully designed and tightly controlled geometry at the macro- or nanoscale. We introduce a class of nanoscale mechanical metamaterials created by forming continuous corrugated plates out of ultrathin films. Using a periodic three-dimensional architecture characteristic of mechanical metamaterials, we fabricate free-standing plates up to 2cm in size out of aluminium oxide films as thin as 25nm. The plates are formed by atomic layer deposition of ultrathin alumina films on a lithographically patterned silicon wafer, followed by complete removal of the silicon substrate. Unlike unpatterned ultrathin films, which tend to warp or even roll up because of residual stress gradients, our plate metamaterials can be engineered to be extremely flat. They weigh as little as 0.1gcm−2 and have the ability to ‘pop-back’ to their original shape without damage even after undergoing multiple sharp bends of more than 90°.

Saturday, February 22, 2014

Nanoscale pillars could radically improve conversion of heat to electricity, say CU-Boulder researchers

February 20, 2014 • Natural Sciences, Engineering, Energy • Discovery & Innovation University of Colorado Boulder scientists have found a creative way to radically improve thermoelectric materials, a finding that could one day lead to the development of improved solar panels, more energy-efficient cooling equipment, and even the creation of new devices that could turn the vast amounts of heat wasted at power plants into more electricity. The technique—building an array of tiny pillars on top of a sheet of thermoelectric material—represents an entirely new way of attacking a century-old problem, said Mahmoud Hussein, an assistant professor of aerospace engineering sciences who pioneered the discovery. The thermoelectric effect, first discovered in the 1800s, refers to the ability to generate an electric current from a temperature difference between one side of a material and the other. Conversely, applying an electric voltage to a thermoelectric material can cause one side of the material to heat up while the other stays cool, or, alternatively, one side to cool down while the other stays hot. - See more at:
In a paper published in the journal Physical Review Letters, Hussein and Bruce Davis demonstrate a Nanophonic Metamaterial: 
Phys. Rev. Lett. 112, 055505 – Published 7 February 2014
Bruce L. Davis and Mahmoud I. Hussein


We present the concept of a locally resonant nanophononic metamaterial for thermoelectric energy conversion. Our configuration, which is based on a silicon thin film with a periodic array of pillars erected on one or two of the free surfaces, qualitatively alters the base thin-film phonon spectrum due to a hybridization mechanism between the pillar local resonances and the underlying atomic lattice dispersion. Using an experimentally fitted lattice-dynamics-based model, we conservatively predict the metamaterial thermal conductivity to be as low as 50% of the corresponding uniform thin-film value despite the fact that the pillars add more phonon modes to the spectrum.
Comparison of the phonon dispersion and thermal conductivity of a pillared silicon thin film with a corresponding uniform thin film. The dispersion curves are colored to represent the modal contribution to the cumulative thermal conductivity, normalized with respect to the highest modal contribution in either configuration. The full spectrum is shown in (a) and the 0≤ω≤2.5  THz portion is shown in (b). Phonon DOS and the thermal conductivity, in both differential and cumulative forms, are also shown. The gray regions represent the difference in quantity of interest between the two configurations. The introduction of the pillar in the unit cell causes striking changes to all these quantities. [from online abstract: Phys. Rev. Lett. 112, 055505 – Published 7 February 2014]

Saturday, February 15, 2014

Using Oxford Instriments OpAl TiN ALD to create high strength low weight Nano Meta Materials

Fabrication and deformation of three-dimensional hollow ceramic nanostructures
Dongchan Jang, Lucas R. Meza, Frank Greer, Julia R. GreerNature Materials, 12 (2013) 893–898, DOI:doi:10.1038/nmat3738
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Above: Skeletal natural biological materials versus TiN nanolattices.

In the analysis of complex, hierarchical structural meta-materials, it is critical to understand the mechanical behavior at each level of hierarchy in order to understand the bulk material response. We report the fabrication and mechanical deformation of hierarchical hollow tube lattice structures with features ranging from 10 nm to 100 μm, hereby referred to as nanolattices. Titanium nitride (TiN) nanolattices were fabricated using a combination of two-photon lithography, direct laser writing, and atomic layer deposition. The structure was composed of a series of tessellated regular octahedra attached at their vertices. In situ uniaxial compression experiments performed in combination with finite element analysis on individual unit cells revealed that the TiN was able to withstand tensile stresses of 1.75 GPa under monotonic loading and of up to 1.7 GPa under cyclic loading without failure. During the compression of the unit cell, the beams bifurcated via lateral-torsional buckling, which gave rise to a hyperelastic behavior in the load–displacement data. During the compression of the full nanolattice, the structure collapsed catastrophically at a high strength and modulus that agreed well with classical cellular solid scaling laws given the low relative density of 1.36 %. We discuss the compressive behavior and mechanical analysis of the unit cell of these hollow TiN nanolattices in the context of finite element analysis in combination with classical buckling laws, and the behavior of the full structure in the context of classical scaling laws of cellular solids coupled with enhanced nanoscale material properties.

Screendump from the video below, showing the fabrication method of the 3D architected nano meta materials described in the Nature publication above.

Video from Solve for X - Julia Greer - 3D Architechted Nano Metamaterials at World Economic Forum.

According to the information I have the ALD TiN process was performed in an OpAL Atomic Layer Deposition System from Oxford Instruments

The Julia Greer Group at Caltech:

Idea and inspiration for this post taken from the Next Big Future Blog.