Clever geometry is the basis of a new material that is said to be ideal for secure data encryption and dense optical information storage [Adv. Mater., 16, 516 (2004)”>.
The material consists of a lattice of onionlike spheres in which the particle core and its layers each contain a different dye. The material can hold four or more pieces of information in one spotâ€”not just two as in binary optical data storage. And it opens a door to high-density three-dimensional optical data storage.
ENCAPSULATED In a three-dye system, core, shell, and matrix are labeled with separate dyes.
â€œThe approach is really simple,â€ says lead researcher Eugenia Kumacheva, associate professor of chemistry at the University of Toronto, who worked with postdocs Ilya Gourevich and Hung H. Pham and microscopist James E. N. Jonkman. They start with colored colloidsâ€”polymeric nanospheres labeled with a dyeâ€”for example, an ultraviolet dye. Then they envelop the nanosphere, what Kumacheva calls the core, with a shell of another polymer labeled with a dye that has a spectrum entirely distinct from the firstâ€”say, a visible dye. Any number of dye-polymer shells can be added. The last shell then becomes the matrix that holds the layered particles.
Chemical & Engineering News
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Volume 82, Number 16