Conclusion and References

Nanomaterials on Earth and Beyond Series

Conclusion:

This article only glances over the many ways in which nanotechnology is changing how things are built on earth and a few ideas on how it can help our journey into space.  Advances in nanomaterials such as carbon nanotubes are setting the precedence for making light weight solar sails, advanced energy storage devices, star-trek like tri-coders, and the space elevator.  Nanomaterials injected into concrete and steel has resulted in high strength and light-weight materials that can withstand harsh conditions on earth and elsewhere.  Several research and development activities around the world are constantly improving these materials’ properties and introducing several new nanotechnology-based products.

References:

Fujishima, A. et. al., “Electrochemical Photolysis of Water at a Semiconductor Electrode”, Nature, 1972, 238 ,5358, 37–8.

Osburn, L, “Literature review on the application of titanium dioxide reactive surfaces on urban infrastructure for depolluting and self-cleaning applications”, 5th Post Graduate Conference on Construction Industry Development, Bloemfontein, South Africa, 16-18 March 2008.

Hogan, J, “Smog-busting paint soaks up noxious gases”. New Scientist, 2004.

Guerrini, G.L. et. al., “White cement and photocatalysis Part 1: Fundamentals”, First Arab International Conference and Exhibition on the use of White Cement,  Cairo, Egypt 28-30 April 2008.

Fujishima, A. et. al. , “Titanium dioxide photocatalysis”,  Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 2000,  1,1, 1–21.

Halford, B.,  “Building Small: Nanotechnology makes inroads in the construction industry”, Greenharmonyhome.com, June 2011.

DeVolder, M.F.L. et. al., “Carbon Nanotubes: Present and Future Commercial Applications”, Science, 2013, 339, 535-539.

O’Donell, S. et. al. , “Potential Impact of Carbon Nanotube Reinforced Polymer Composite on Commercial Aircraft Performance and Economics”, American Institute of Aeronautics and Astronautics, 2005, 1-10.

Mann, S., “Nanotechnology and Construction”, European Nanotechnology Gateway- Nanoforum Report, 2006.

Bauhofer, W., “A review and analysis of electrical percolation in carbon nanotube polymer composites”, Compos. Sci. Technol. , 2009, 69, 1486.

O’Rouke, M.J. et. al. “Electromagnetic Interference Shielding via Carbon Nanotubes” , Biennial Research and Technology Development Report- Johnson Space Center, 2007, 63-65.

Greenemeier, L., “Staying Out of a Jam: Air Force Looks at Nanotube Sheets for Electromagnetic Shielding”, Scientific America, October 2009. http://www.scientificamerican.com/article.cfm?id=carbon-nanotube-emi-protection

Chou, T.W. et. al. , “An assessment of the science and technology of carbon nanotube-based fibers and composites”, Composites Science and Technology, 2010,  70,  1, 1-19.

Coleman, J.N. et. al. “Mechanical Reinforcement of Polymers Using Carbon Nanotubes”, Advanced Materials, 2006, 18, 6, 689-706.

Beigbeder, A. et. al., “Preparation and characterisation of silicone-based coatings filled with carbon nanotubes and natural sepiolite and their application as marine fouling-release coatings”, Biofouling, 2008, 24, 4, 291-302.

Kashiwagi, T. et. al., “Nanoparticle networks reduce the flammability of polymer nanocomposites”, Nat. Mater. , 2005, 4, 928-933.

Grebler, S. et. al. “Nano in the Construction Industry”, Nano Trust Dossiers- Institute of Technology Assessment of the Austrian Academy of Sciences , 2012, 32, 1-6.

Sanchez, F. et. al.  “Nanotechnology in concrete-a review.” Construction and Building Materials, 2010, 24, 11, 2060-2071.

The Gärtnerplatz Bridge website, http://www.gaertnerplatzbruecke.de.

Brain, M. “What if we lived on the moon? – Moon Colony Resources”, Howstuffworks website. http://science.howstuffworks.com/what-if-moon-colony1.htm

Peter, C.C. et. al. , “Moon Dust Telescopes, Solar Concentrators, and Structures”, American Astronomical Society, AAS Meeting #212, #25.07; Bulletin of the American Astronomical Society, 2008, 40, 223. http://news.nationalgeographic.com/news/2008/06/080604-lunar-cement.html

Sandvik Materials Technology, http://www.smt.sandvik.com/en/

MMFX Steel, http://www.mmfx.com/

Siceloff, S., “Shuttle Liftoffs Require Precision Launch Pad”, NASA’s John F. Kennedy Space Center, 2011.  http://www.nasa.gov/mission_pages/shuttle/flyout/launchpadflyout.html

BASF, http://www.basf.de

Placido, F., ‘Thin films and coatings: atomic engineering”, Proceedings, 1st Inter. Symp. on Nanotechnology in Construction, 2003.

Tomczak, J.M., “Materials design using correlated oxides: Optical properties of vanadium dioxide”, Europhysics Letters, 2009, 86, 3, 37004.

JNC Group. http://www.jnc-group.com/index.htm.

Norris, A. et. al. “Temperature and Moisture monitoring in concrete structures using embedded nanotechnology/Microelectromechanical systems (MEMS) sensors”, Construction and Building Materials,2008,  22, 111-120.

Song et. al. “Health monitoring of concrete piles using piezoceramic-based smart aggregates”, Proc. SPIE, Health Monitoring of Structural and Biological Systems, 2010, 7650.

Li et. al.  “Carbon Nanotube Based Chemical Sensors for Space and Terrestrial Applications”, Meet. Abstr., 2009, 19,6, 7-15.

Suaser, B. “Nanosensors in Space”, 2007. http://www.technologyreview.com/news/408190/nanosensors-in-space/

Green, M.A., “High-efficiency silicon solar cells”, Proc. SPIE - Electronics and Structures for MEMS, 2009, 3891.

Ecosolargy Inc. http://www.ecosolargy.com/

Chou, S.Y. et. al. “Ultrathin, high-efficiency, broad-band, omni-acceptance, organic solar cells enhanced by plasmonic cavity with subwavelength hole array”, Optics Express, 2013, 21, s1, A60-A76.

Dai et. al. , “Carbon nanomaterials for advanced energy conversion and storage”, Small, 2012, 8, 1130-1166.

Matsumoto, T. et. al. “Reduction of Pt usage in fuel cell electrocatalysts with carbon nanotube electrodes”, Chem. Commun., 2004, 2004, 7, 84-841.

Le Goff, A. et. al., “From Hydrogenases to Noble Metal–Free Catalytic Nanomaterials for H2 Production and Uptake”, Science, 2009, 329, 5958, 1384-1387.

Stauber, L. , “New Technologies Replace Chemical Batteries”, NASA Glenn Technology Transfer, http://www.nasa.gov/topics/technology/hydrogen/chem_battery.html

Van der Veen, M.H. et. al. “Electrical and Structural Characterization of 150 nm CNT Contacts with Cu Damascene Top Metallization”, 2012 IEEE International Interconnect Technology Conference, 2012, 1, 1, 1-4.

Conway, B.E., “Electrochemical  Supercapacitors—Scientific Fundamentals And  Technological Applications”, Springer, 1999.

“Audacious & Outrageous: Space Elevators”, NASA, 2000, http://science.nasa.gov/science-news/science-at-nasa/2000/ast07sep_1/

The Spaceward Foundation, http://www.spaceward.org/elevator

 

Intro | Nanomaterials | Nanocrete |
Nanosteel | Nanosurfaces | Nanosensors | Nanoenergy | Space-Elevator | Conclusion-Ref

Bringing it all Together: The Space Elevator

Nanomaterials on Earth and Beyond Series

A Russian scientist, Konstantin Tsiolkovsky, first proposed the space elevator in early 1895. It is essentially a long cable extending from earth’s surface into space with its center of mass at geostationary Earth orbit (GEO), 35,786 km in altitude. The cable will have electromagnetic vehicles traveling along it, which would act as a mass transportation system for moving people, payloads, and power between Earth and space. The cable would be tethered to the top of a base tower approximately 50 km tall and the other end attached to a large counterbalance mass beyond geostationary orbit, perhaps an asteroid moved into place for that purpose (42). -article continued below illustration-

nanotechnology-and-the-space-elevator-earth-and-beyond-series

nanotechnology-and-the-space-elevator-earth-and-beyond-series

For space elevator to be a reality, there is a need for very strong materials that don’t collapse on there own weight. CNTs are sought out as the material for building these space elevators. According to Ben Shelef co-founder of the Spaceward Foundation (43), the hindrance for achieving this space elevator technology is the unavailability of a macroscopic thread that takes full advantage of CNTs incredible strength.  Beyond tethering technology, all other challenges are relatively simple. In addition to university research in this topic, NASA has sponsored a $4M Space elevator competition.

Thus with nanotechnology, space flights and space colonization will not be merely science fiction but a reality.

Intro | Nanomaterials | Nanocrete |
Nanosteel | Nanosurfaces | Nanosensors | Nanoenergy | Space-Elevator | Conclusion-Ref

Nanomaterials and Energy

Nanomaterials on Earth and Beyond Series

nano-filled-solar-panel-surfaces-prevent-dust-blockage-for-years

nano-filled-solar-panel-surfaces-prevent-dust-blockage-for-years

Sun is the ubiquitous source of energy in our solar system, and solar cell applications for space date back to 1950. Traditional solar cells made of mostly silicon or germanium are bulky and have very poor efficiency (efficiency is the ratio of the electrical output to the incident energy from sunlight and calculated based on a cells power output, surface area of the cell and the input light).  Because of poor efficiencies (Silicon cells have 18% efficiency) (33) solar cells need to be arranged in large arrays to generate enough power. In fact the mars rover currently has multi-panel solar array for power. The solar panel is subjected to degradation due to anticipated dust coverage on the solar panels. EcoSolargy (34) is attacking this problem on earth using nano- coating techniques mentioned in previous sections to fill tiny holes that typically would accumulate dirt, dust, or water, and has increased efficiency by 35 percent over a 20-year period.  This is a huge step for space installations where sand storms and space dusts are common.

nanomesh-from-graphene_from-nanotechnology-on-earth-and-beyond

Graphene Nanomesh

Nanotechnology is also paving way for flexible, low cost and light weight solar cells especially with organic photovoltaic cells made of graphene and zinc oxide nanowires. Princeton university researchers recently demonstrated 3 times higher efficiency than conventional solar cells by applying a “nano-mesh” to plastics (35). The nano-mesh dampens reflection, traps light and converts them into electrical energy (existing technologies cannot fully capture all the light entering the cell). While these solar cells are marketed towards flexible chargers for laptops and cellphones, “Wall-E” like robots roaming the extra-solar planets’ surfaces or mining asteroids for minerals are not too far in the future.

On the storage side, small amounts of CNT powder (1% by weight) are blended with active materials and a polymer binder (such as LiCoO2 cathodes and graphite anodes) that have wide usage in lithium ion batteries for mobile computers and phones (36). CNTs enhance the capability and cycle life by providing increased electrical connectivity and mechanical integrity. CNTs are also used as catalyst support in fuel cells, which can potentially reduce platinum (Pt) usage by 60% compared with carbon black (37).

nano-enhanced-honda-ultracapacitor-example

nano-enhanced-honda-ultracapacitor-example

Furthermore doping i.e. intentionally introducing impurities into CNTs may enable fuel cells that do not require platinum (Pt) (38). But the most promising of energy storage for space applications would be in ultracapacitors.  Ultracapacitors can store significantly more charge than regular capacitors, they can be recharged within seconds over a million times, have 10 to 100 times greater power densities, and can hold that charge over a very long period (39). CNT used in a 40-F ultracapacitors (40) produced an energy density (amount of energy stored per unit volume) of 16 Wh/Kg and a power density (amount of power stored per unit volume) of 10 KW/kg (a standard Li-Ion battery has a power density of 250-340 W/kg at 3.5 V).Accelerated testing forecasted a 16-year lifetime for these batteries.  Ultracapacitors could be applied to many emerging technologies such as electric vehicles (NASA has been testing this technology on their light hybrid electric transit buses), satellite propulsion and pulse power applications (41).

An important application where all the technologies mentioned earlier in this article will have a huge impact is in the realization of a “space elevator”.

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Nanosteel | Nanosurfaces | Nanosensors | Nanoenergy | Space-Elevator | Conclusion-Ref

Nano-Sensors

Nanomaterials on Earth and Beyond Series

nanotechnology-MEMS-Micro-Electro-Mechanical-Systems

MEMS-Micro-Electro-Mechanical-Systems Example

Sensors based on nanotechnology also offer great potential for developing smart materials and structures, which have ‘self-sensing’ and ‘self-actuating’ capability. These can be implanted in concrete and can serve in quality control and help monitor durability. Cheap nano-sensors based on micro-electromechanical systems (MEMS) devices and carbon nanotube sensors could be embedded into buildings to give early warning of defects that make them more vulnerable to earthquakes. While the MEMS device monitors internal temperature and moisture, the nanotube sensors detect cracks forming inside the concrete. The data is then wirelessly transmitted to a laptop (29).  In the future, sensors like smart aggregates (a low cost piezoceramic (ceramic materials that produce a voltage under mechanical deformation and vice versa)-based multi-functional device sensor) (30) will help measure the density and viscosity of the concrete along with parameters that influence durability (e.g. temperature, moisture, relative humidity, pH, vibrations) (9).

nanotechnology-carbon-nanotube-sensors-midstar-1-satellite

nanotechnology-carbon-nanotube-sensors-midstar-1-satellite

It is crucial to be able to effectively measure the level of various gases and toxins that may have seeped into a spacecraft or closed colony environment in space.  This is crucial especially in long missions, when contaminants build up and threaten the health of crew members and/or the onboard equipment. NASA Ames Research Center and the Goddard Space Flight Center sent a chemical sensor made of arrays of carbon nanotubes (31) weighing only one gram into space on board the Naval Academy’s Midstar-1 satellite (32).  The sensor was able to endure extreme vibrations and gravity changes that occur during launch as well as the intense conditions in space, like changing temperature and pressure cycles.

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Nanosteel | Nanosurfaces | Nanosensors | Nanoenergy | Space-Elevator | Conclusion-Ref

Nanomaterials and Surfaces

Nanomaterials on Earth and Beyond Series

Nanotechnology infused coatings - nanocoatings

Nanotechnology infused surfaces

Coatings are expected to constitute the largest application for nanomaterials in near-term construction. Nanomaterial coatings bind to the base material to produce a surface of the desired functional and protective properties (fire protection, heat insulation and corrosion protection).  These coatings are usually produced by using Chemical Vapor Deposition (CVD- a chemical process to produce high performance, high purity solid materials by passing volatile vapors over a substrate.), Dip (i.e. immersing a substrate into the nanomaterial solution), and Spray (i.e. spraying the substrate with the nanomaterial solution)  (9).

Some of the current nanomaterial coatings in the construction industry include architectural paints, water sealers, deck treatments, scratch-resistance coatings, anti-microbial coatings, self-cleaning surfaces, UV blocking , stain resistant and odor resistant.

The most prominent of coating materials is TiO2, which was covered in more detail in an earlier section. Pilkington, St. Gobain Co., and others are already marketing self-cleaning glasses based on these TiO2 coatings. Another approach to creating self-cleaning glass is based on replicating the spotless lotus leaves and marketed by BASF as “lotus-spray” products (25). The product is expected to be 20 times more water-repellent property than a smooth, wax coating and retain its lotus effect even after an abrasion with sandpaper. Nanomaterial coatings can also be used to build intelligent glass that blocks heat but not light (26). For example vanadium dioxide coatings can be used to absorb infrared light above a certain temperature (27). Additionally coatings using an acrylic primer made up of a unique combination of Nano structures called NanoCNB (28) act as thermal insulators by reflecting heat back to the room.  This technology originally developed by NASA to combat high temperatures encountered by space shuttles, acts by altering the floor/walls ability to absorb heat from the room, thus reflecting the heat back into the room.

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Nanosteel | Nanosurfaces | Nanosensors | Nanoenergy | Space-Elevator | Conclusion-Ref