Switching Colors with Electricity
The content you've requested is available without charge only to active Sigma Xi members and American Scientist subscribers.
If you are an active member or an individual subscriber, please log in now in order to access this article.
If you are not a member or individual subscriber, you can:
A low jolt of electricity has an unusual effect on certain materials: It changes their color. Such electrochromic materials may change color, darken or go clear in response to the current, and then maintain that change when the power is switched off. A second jolt can completely reverse the change. The reaction occurs due to the chemical process of oxidation and reduction (collectively called redox processes), where electrons are lost or gained, respectively. Redox causes a shift in the bands of the electromagnetic spectrum where the chemical will absorb light, and such shifts in the visible region induce color changes. The effect has been observed since the early 19th century, but Mortimer describes recent experiments to elucidate the cause, as well as how materials are being engineered for practical use. Current commercial devices include car mirrors and plane windows that dim automatically to reduce glare. Proposed applications include multicolor displays, protective eyewear, camouflage materials and chameleonic fabrics.
Connect With Us:
An early peek at each new issue, with descriptions of feature articles, columns, and more. Every other issue contains links to everything in the latest issue's table of contents.News of book reviews published in American Scientist and around the web, as well as other noteworthy happenings in the world of science books.
To sign up for automatic emails of the American Scientist Update and Scientists' Nightstand issues, create an online profile, then sign up in the My AmSci area.
JSTOR, the online academic archive, contains complete back issues of American Scientist from 1913 (known then as the Sigma Xi Quarterly) through 2005.
The table of contents for each issue is freely available to all users; those with institutional access can read each complete issue.
View the full collection here.
Receive notification when new content is posted from the entire website, or choose from the customized feeds available.