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Nanotechnology and Self-Cleaning

Molecules can have interesting, even revolutionary, properties. Nanotechnology is the science of studying matter from the perspective of nanometers, or billionths of a meter, the scale at which molecules work. In 2011, nanotechnology is still largely in the research stage. You can, however, walk into a store and buy clothes that repel dirt, thanks to designer molecules.

Molecular Design
- Using computer software, a scientist can design, study and test molecules on a display screen, just as engineers model bridges, cars and aircraft before building them. The software accurately portrays the complex interactions between atoms. By modeling molecules on a computer, the scientist saves months or years of traditional chemical experiments. With the time saved, she can more fully explore the nuances of different atomic arrangements. When she is satisfied with the molecule design, she takes it to a chemist, who makes it.
Chemical Properties
- Certain chemicals and substances repel water; chemists call these hydrophobic. Others, known as lipophobic, repel oil. Teflon, for example, repels both water and oil. Molecules with these properties have a structure that repels droplets by static electricity. Water does not soak a hydrophobic material; instead, it beads up and rolls off. As a self-cleaning material prevents splashed liquids from leaving a stain, the molecules in the material will have hydrophobic and lipophobic properties.
Microscopic Shapes
- In addition to static electricity, molecules can repel water and other fluids through surface tension. Tiny hair-like structures, similar to those found on birds' feathers and the legs of insects, cause water to bead. At the level of these small features, water does not flow. One of nanotechnology's objectives is the design and manufacture of tiny structures such as these, so they can be applied to a variety of surfaces, including clothing and upholstery.
Active Materials
- Scientists pursuing nanotechnology take cues from the complex molecules of living things. For example, the "motor" that powers a bacterium's flagellum, a whip-like propeller, has been analyzed at the molecular level. Someday, nanotechnology may produce active materials consisting of tiny, computer-controlled molecular machines. Goods made of these materials might, for example, actively repel, absorb or decompose stains and dirt, requiring little or no cleaning.

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