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Good Things in Small Packages

Building functional materials and materials systems often requires the development of new methods for compartmentalizing things -- keeping one part of the system separate from all others -- perhaps in anticipation of mixing at some later time. [Created Droplet Shells] Examples of compartmentalization abound in natural materials systems; indeed the basic building blocks of all organisms -- biological cells -- are fundamentally compartments that define the organism as separate from its environment and that allow the organism to accomplish the many tasks essential to its survival.

Research in IRG I has led to a simple and versatile new method of building small compartments for use in the design of complex composite materials. The method uses a water-soluble compound (tetrakismethoxyethoxyethoxysilane, TMEES) to coat the surfaces of droplets dispersed in an aqueous medium. Several minutes after mixing, the TMEES surface coating develops into a glassy shell that replicates the size and shape of the droplet, and that can be separated from the suspension and further stabilized by heating if necessary (see figure). The use of such shells to sequester reactive materials in complex composites is under investigation.

For further information, please contact Professor David Tirrell, team leader of IRG 1: (626) 395-3140 or tirrell@cheme.caltech.edu.

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