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July 13, 2012

Aerographite is the lightest material, strong and could enable Statites

The world's lightest solid material has been touted by a team from the Technical University of Hamburg and the University of Kiel in Germany.


New aerographite material is worlds lightest. It is composed of 99.99% air, aerographite has an ultra low density of just 0.2 mg/cm³ and is said to demonstrate extraordinary electrical properties.

Researchers Professor Karl Schulte and Matthew Mecklenburg created it from a network of hollow carbon tubes grown at the nano and micro scales.

According to Prof Schulte, aerographite's sparse nature means it can be compressed by a factor of a thousand, with the ability to then spring back to its original size. The material is also capable of supporting 35 times more weight than the same mass of aerogel.

Because it is electrically conductive and chemical-resistant, the researchers believe it could potentially find its way into devices such as batteries.


A microscope image of aerographite, which is now officially the world's lightest solid material (Image: Technical University of Hamburg)

Advanced Materials - Aerographite: Ultra Lightweight, Flexible Nanowall, Carbon Microtube Material with Outstanding Mechanical Performance

An ultra lightweight carbon microtube material called Aerographite is synthesized by a novel single-step chemical vapor deposition synthesis based on ZnO networks, which is presently the lightest known material with a density smaller than μg/cm3. Despite its low density, the hierarchical design leads to remarkable mechanical, electrical, and optical properties. The first experiments with Aerographite electrodes confirm its applicability.




Material selection map with design criteria for free standing beam. E/r2 is the important parameter if the cross sectional area is variable.



Material selection map showing Young's Modulus over density with three design criteria.


27 pages of supplemental information


a-i) SEM images showing surface layers of Aerographite in variations of several evaluated processes. a) Low magnification of fractured Aerographite ligament. b) Graphitic layer fragment of former junction point of two Aerographite parts in background intact connections of visible Aerographite ligaments. c) High magnification of area in b (wrinkled surface of graphitic layers visible). d-f) Examples of different process delivering very smooth surfaces of graphitic layers. g) Tip of a Aerographite ligament with only low wrinkling and opened shell due to fracture of former junction. g) Detail of an Aerographite ligament. h) Overlapping of Aerographite ligaments forming a hole. i) Inside view of an open Aerographite ligament with minor wrinkling with hollow spherical carbon layer particles.



Photographs and light microscopy images of typical Aerographite specimens. a) Cross sectional view on an Aerographite sample b) Photographs of an Aerographite sample before the infiltration with epoxy resin. c) Light microscopy on epoxy resin infiltrated and cured Aerographite specimen (RIMR135/RIMH137 epoxy system). Since Aerographite is hydrophobic, an excellent wetting behavior is given for epoxy systems (all scales in cm).

Statite Solar Sail of 3 mm thick Aerographite

A Statite solar sail has a balance between the gravity of the sun and solar pressures. Aerographite appears to make this feasible and requires large amounts to be produced.

Wrapping the Sun in “statites” – optically levitated structures – is perfectly reasonable and avoids the issues of the science-fictional Shell Habitat. Such structures, however, have a vulnerability, from in-falling meteoroids and comets.

For a perfect absorber the ratio between the outward force of sunlight to the inward pull of gravity is 1:1300. That means energy collecting statites need to be very thin. Interestingly, because the sunlight and gravity decline in intensity via the inverse square law, except in very close proximity to the Sun, a statite able to levitate near the Earth will do so at any radial distance from the Sun. The exception is when close to the Sun and instead of being a “point source”, the Sun is a great big wall of light. For materials purposes we’ll assume an operating temperature of 1000 K and 50% conversion efficiency, which puts our collector at about 0.1 AU. Here the sunlight is 100 times stronger than at Earth’s orbit.

A statite deployed around our own sun would have to have an overall density of 0.78 grams per square meter of sail.

3 millimeter thick aerographite would have the right density to build a Statite solar sail.


Statites make a Dyson Bubble Feasible

Harnessing all of the Sun's energy with Statites would take about 100 trillion tons of Aerographite.

10 tons deployed near the sun would collect 10 trillion watts about the energy generated by our current civilization.

100,000 tons deployed near the sun would collect 100 petawatts equal to all the solar energy that hits the earth.


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