Polymers that shrink from light.Polymers that shrink from Verb 1. shrink from - avoid (one's assigned duties); "The derelict soldier shirked his duties" fiddle, shirk, goldbrick avoid - refrain from doing something; "She refrains from calling her therapist too often"; "He should avoid publishing his wife's light Muscles contract when their natural polymers respond to nerve impulses nerve impulse n. A wave of physical and chemical excitation that moves along a nerve fiber in response to a stimulus. . Materials scientists strive develop synthetic polymers that similarly respond to stimuli such as light by changing their shape, permeability or other properties. Earlier this year, Toyoichi Tanaka of the Massachusetts Institute of Technology Massachusetts Institute of Technology, at Cambridge; coeducational; chartered 1861, opened 1865 in Boston, moved 1916. It has long been recognized as an outstanding technological institute and its Sloan School of Management has notable programs in business, synthesized polymers that respond to ultraviolet light Ultraviolet light A portion of the light spectrum not visible to the eye. Two bands of the UV spectrum, UVA and UVB, are used to treat psoriasis and other skin diseases. . Now, he and Atsushi Suzuki of Yokohama (Japan) National University have made a polymer that shrinks when subjected to light of visible wavelengths and reswells in the dark. In the July 26 NATURE, they suggest that the responsiveness to visible rather than ultraviolet light makes this polymer a more versatile candidate for applications such as artificial muscles and mechanical actuators for robots. The responsive polymer gel consists mainly of linked N-isopropylacrylamide molecules. By adding links of copper chlorophyllin, a light-sensitive molecule, the researchers created a polymer that harvests light energy and distributes it within the polymer as heat. The heat induces a size-reducing phase change in the polymer, skin to water vapor condensing con·dense v. con·densed, con·dens·ing, con·dens·es v.tr. 1. To reduce the volume or compass of. 2. To make more concise; abridge or shorten. 3. Physics a. into a liquid, Tanaka says. In their paper, the researchers report a size reduction of about two-thirds, but Tanaka says he expects future formulations to shrink several hundred-fold in response to visible light. |
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