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Physicists Develop Carbon Nanotube Aerogel Optimizing Strength, Shape And Conductivity

Date:
May 28, 2007
Source:
University of Pennsylvania
Summary:
Researchers have created low-density aerogels made from carbon nanotubes, CNTs, that are capable of supporting 8,000 times their own weight. The new material also combines the strength and ultra-light, heat-insulating properties of aerogels with the electrical conductivity of nanotubes.
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Images of aerogels. a) Macroscopic pieces of 7.5 mgmL//--1// CNT aerogels. Pristine CNT aerogel (left) appears black, whereas the aerogel reinforced in a 1 wt% PVA bath (right) is slightly gray. b) Three PVA-reinforced aerogel pillars (total mass = 13.0 mg) supporting 100 g, or ca. 8000 times their weight. c) This scanning electron microscopy (SEM) image of a critical-point-dried aerogel reinforced in a 0.5 wt% PVA solution (CNT content = 10 mgmL//--1//) reveals an open, porous structure. d) This high-magnification transmission electron microscopy (TEM) image of an un-reinforced aerogel reveals small-diameter CNTs arranged in a classic filamentous network.
Credit: Image courtesy of University of Pennsylvania

Researchers at the University of Pennsylvania have created low-density aerogels made from carbon nanotubes, CNTs, that are capable of supporting 8,000 times their own weight.  The new material also combines the strength and ultra-light, heat-insulating properties of aerogels with the electrical conductivity of nanotubes.

Aerogels are unique, low-density materials created by replacing the liquid component of a gel with gas and are normally constructed from silicon dioxide or other organic polymers.  They are currently used as ultra-light structural materials, radiation detectors and thermal insulators.  Aerogels made from CNTs offer advantages to current aeroegels that point towards future applications in chemical or biological sensors.

A collaboration led by Arjun G. Yodh and Jay Kikkawa of the department of Physics and Astronomy at Penn created the aerogels by freeze-drying or critical-point-drying CNT networks suspended in fluid.  The process produces a carbon nanotube network whose carbon concentration, electrical conductivity and strength can be manipulated.  Critical-point-drying demonstrated reproducible conductivity in the aerogels.

The team also maintained control of the density, microscopic structure and shape of the CNT aerogels, as well as their strength. By adding small amounts of polyvinyl alcohol during processing, very strong aerogels were created.  The nanotube dispersion process was optimized to create an even distribution of nanotubes within the aerogel.

The findings were reported in the journal Advanced Materials.

The study was conducted by Yodh, Kikkawa, Mateusz B. Bryning, Daniel E. Milkie and Lawrence A. Hough of Penn's Department of Physics and Astronomy and Mohammad F. Islam of the Department of Chemical Engineering at Carnegie Mellon University.

The research was supported by the National Science Foundation.


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University of Pennsylvania. "Physicists Develop Carbon Nanotube Aerogel Optimizing Strength, Shape And Conductivity." ScienceDaily. ScienceDaily, 28 May 2007. <www.sciencedaily.com/releases/2007/05/070524154616.htm>.
University of Pennsylvania. (2007, May 28). Physicists Develop Carbon Nanotube Aerogel Optimizing Strength, Shape And Conductivity. ScienceDaily. Retrieved September 5, 2015 from www.sciencedaily.com/releases/2007/05/070524154616.htm
University of Pennsylvania. "Physicists Develop Carbon Nanotube Aerogel Optimizing Strength, Shape And Conductivity." ScienceDaily. www.sciencedaily.com/releases/2007/05/070524154616.htm (accessed September 5, 2015).

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