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Airdate: May 15, 2017
Scientist: Pedro Alvarez

Nanoparticles A Whole Lot of Surface

Nanoparticles  A Whole Lot of Surface
How does making something smaller change its nature?

Transcript:
Nanoparticles A Whole Lot of Surface

When particles of matter are reduced in size to be come small really small, their properties can change. It's the basis for many of the advances of nanotechnology. But how does making something smaller change its nature? I'm Jim Metzner and this is the Pulse of the Planet.

Alvarez: The word nano is a Greek prefix that stands for dwarf. Mathematically, we take it to mean 1 billionth of a meter, so we're talking at about a very, very small scale.

Pedro Alvarez is the George R. Brown Professor of engineering at Rice University.

Alvarez: Most materials on a per-atom basis become far more reactive at the nano scale, which enables us to develop superior absorbents. So you can use these materials to more selectively treat water pollutants and remove them in a more cost-effective way.
Much of the extraordinary properties that are exhibited at the nano scale relates to the very high surface-to-area ratio. Nanomaterials are essentially all surface, and because they offer so much surface area, they offer greater opportunities to interact with the environments or with biological systems, or with target pollutants. But also at that scale, you start seeing photonic properties were they absorb light and convert it to heat more easily, which you can take advantage of to generate vapor and distilled water, as a relatively inexpensive way to desalinate water from the ocean.
One example might be carbon, (which) is very good as a photothermal material, that is a material that absorbs sunlight and converts it to highly localized heat, sufficient heat to generate vapor.

Pulse of the Planet is made possible in part by the Center for Earth and Environmental Nanotechnology and the National Science Foundation.