Jeff Brinker, a senior scientist at Sandia National Labs and a University of New Mexico professor, has discovered a new way of detecting mechanical, chemical, and thermal stress. Brinker uses intelligent nanostructures made from conjugated polymers that change from blue to red when changes in mechanical stress and temperature are introduced. The polymers change back to their original color when the stress and temperature changes are removed. The structures also change color in the presence of different solvents and chemicals. This colorful feat occurs at the nano level and involves linking monomers into polymers in an orderly fashion. "We have patents in progress on the general idea of self-assembly of nanocomposite materials," says Brinker. "We use surfactants both to direct the formation of the inorganic silica nanostructure and as monomers that become polymers in situ within the nanostructure to form the conjugated polymer," he explains. Conjugated polymers are typically similar to a bowl of entangled spaghetti, but Brinker found a way of organizing them. The materials are prepared by simple evaporation-driven processes like spin-coating, dip-coating, and ink-jet printing. Brinker notes the materials are easily integrated into devices, especially in thin-film form. By controlling interactions between the polymers, he effects the materials' electric and optical properties. The smart materials also serve mechanical functions such as protective coatings and permeation barriers. "Also, it is now recognized that to get better efficiency and function from conjugated polymers, it is necessary to organize them so as to control energy and electron transfer," says Brinker, adding that NASA, a sponsor of his work, is interested in thin films of the smart material for inflatable structures.
Most machine design engineers will survey existing component manufacturers for standard linear guide products, limiting what they can do with their designs. Using extruded aluminum profile guides can customize machine designs while shrinking the bill of materials.
Practically all electronic devices today contain metals that may
be coming from conflict-ravaged African countries. And political pressures will increasingly influence how these minerals are sourced and used in products.
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