Microrockets Fizz Along Tiny devices push themselves forward on
a stream of hydrogen bubbles In an acidic solution, a
microrocket zips around at speeds of up to 1,050 micrometers a
second—not bad for something only about 8 micrometers long, too
small to be seen by the human eye. The minuscule cone-shaped
devices, created by nanoengineer Joseph Wang and his colleagues
at the University of California, San Diego, work best in the
kinds of harsh, acidic environments that are usually detrimental
to most machines and sensors. As the team reported in the
January 18 issue of the Journal of the American Chemical
Society, the device is powered by a reaction commonly known in
high school chemistry. Wang and his colleagues fabricate the
rockets with a tubular template that has an opening pore that is
only 1 to 2 micrometers wide. The template’s inner wall is first
coated with a polymer film, then deposited with a layer of zinc.
After the microrocket is complete, the template is dissolved
away. When placed in an acidic so