November 5, 2008 -- Scientists in Canada
are reporting progress toward a new type of “liquid mirror” — mirrors made with
highly reflective liquids — whose shape can be changed to provide superior
optical properties over conventional solid mirrors. The advance could lead to
improved instruments for diagnosing eye disease, more powerful telescopes, and
other applications, the researchers say. Their research will be described in the
November 25 issue of ACS’ Chemistry of
Materials, a bi-weekly journal.
In the report, Anna Ritcey,
Jean-Philippe Dery, and Ermanno Borra note that “liquid mirrors” are not new.
Scientists have long recognized that these liquids could provide a low-cost,
easy-to-use alternative to solid mirrors for a variety of optical applications
while offering the potential for less image distortion. Researchers have
recently developed liquid-mirror telescopes that use mercury as the reflective
material. Mercury, however, is toxic and the shape of the surface can’t be
deformed or adjusted.
The scientists describe development of a new
type of deformable “liquid mirror” composed of magnetic iron particles, ethylene
glycol (a component of automotive antifreeze), and a coating of silver
nanoparticles. These materials form a highly reflective mirror whose shape can
be changed by adjusting the voltage applied to electromagnets placed below the
liquid, allowing the user to fine-tune the mirror’s optical properties. In lab
studies, the new material showed better reflectivity and stability than current
liquid-mirror materials, the scientists say.
A news release courtesy of American Chemical Society.