2010 R&D 100 Winner
For the past 20 years, researchers have used photochemical techniques in an effort to make cost-efficient, laser-triggered microcapsules for drug delivery, self-repairing paint, or electronics. However, commercial examples have yet to appear because the capsules are difficult to manufacture in bulk. Elevated temperatures are required for just a single batch, and shell walls must be precisely engineered to open at a set wavelength.
In developing Chemicals on Demand, researchers at Lawrence Berkeley National Laboratory, Berkeley, Calif., and the Univ. of California, Berkeley solved these problems by employing interfacial condensation, a nearly instantaneous method for trapping liquid inside a nylon shell, to form an impermeable, robust membrane around a suspension of commercially available light absorbers such as carbon nanotubes.
Carbon nanotubes were the best material available for broad-spectrum absorption of visible and near-infrared light, and when mixed with the encapsulated liquid chemical facilitate the buildup of internal pressure responsible for bursting the microcapsule upon irradiation with light. The microcapsules are robust, losing no more than 4% of liquid contents after up to 64 days.
Technology
Laser-triggered microcapsules
Developers
Lawrence Berkeley National Laboratory
University of California, Berkeley
Development Team
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| Left to right: Jean Fréchet, David Okawa, Alex Zettl, Stefan Pastine |
The Chemicals on Demand Development Team:
Jean Frechet, Lawrence Berkeley National Laboratory
David Okawa, University of California, Berkeley
Stefan Pastine, University of California, Berkeley
Alex Zettl, Lawrence Berkeley National Laboratory
