Featured Research

from universities, journals, and other organizations

Polymer-Based Mirror Outshines All Others

Date:
April 5, 2000
Source:
American Association For The Advancement Of Science
Summary:
A new type of reflective film made from polyester and other polymers reflects light with a brightness and versatility superior to other mirrors, according to a team of researchers at 3M. The first report of these mirror films appears in the 31 March issue of Science.

Washington D.C. -- A new type of reflective film made from polyester and other polymers reflects light with a brightness and versatility superior to other mirrors, according to a team of researchers at 3M. The first report of these mirror films appears in the 31 March issue of Science.

These thin, flexible polymer mirrors should be a boon to fields such as optoelectronics, whose lasers, electronic displays, optical fibers, and other light-related technologies benefit everything from communications, to medicine, to astronomy.

Unlike other mirrors, these can reflect visible light from all angles with great efficiency, report Andrew J. Ouderkirk and colleagues in their Science paper.

The bathroom mirror you face bleary-eyed each morning is made by coating a hard surface with a thin layer of metal. These mirrors reflect light no matter what direction it's coming from. They aren't very useful for high-tech purposes, though, because they absorb some of the light instead of reflecting it.

For applications that require a more efficient reflection, dielectric mirrors are the tools of choice. These mirrors are made of alternating layers of transparent materials that each reflects a small fraction of the light that hits them. When the layers are just the right thickness, the reflected light waves merge and amplify, intensifying the reflection. (Think of a perfectly timed merge between two ocean waves that produces a whitecap.)

For all their brightness, however, conventional dielectric mirrors have an important flaw. Although they work fine when light approaches them straight on, they have trouble reflecting light that hits at certain angles. In fact, the more sharply angled the light beam's path into the mirror, the more poorly the light is reflected. Ultimately, when the path exceeds a certain angle, the mirror stops reflecting altogether. This phenomenon, called Brewster's Law for the scientist who discovered it almost 200 years ago, has long been thought to be an insurmountable drawback to mirrors made of multiple layers of dielectric materials.

Recently, a team of researchers demonstrated that it's possible to make multilayer mirrors that are less choosy about the direction of incoming light (see Science, 27 November, 1998, p. 1679). They used a mixture of organic and inorganic materials to make mirrors that reflected infrared wavelengths. However, Ouderkirk and his colleagues at 3M wanted to use purely organic polymer materials to make mirrors that reflect visible light, which required a different approach.

"Polymers can do things inorganic systems can't. They are commercially available and when made into a multilayer mirror, can have good reflectivity at all angles," Dr. Ouderkirk said.

The mirrors created by Dr. Ouderkirk and his research team, which includes Michael F. Weber, Carl A. Stover, Larry R. Gilbert, and Timothy J. Nevitt, reflect visible light no matter what direction it's coming from. Because they consist of thin, flexible stacks of layered polymers such as polyester, these mirrors are cheap, versatile, and easy to make in large volume.

In a similar fashion to the light hitting a dielectric mirror, some light waves are reflected from the polymer mirrors each time a light beam hits a new layer of material. However, every other layer of these new mirrors is a "birefringent" material, meaning that its crystal structure causes an incoming light beam to split into two rays that travel through at different speeds. By alternating thin films of birefringent and non-birefringent ("isotropic") polymers, Ouderkirk and his colleagues gained much more control over the interactions of the reflected light beams. Ultimately, the researchers were able to skirt Brewster's law and induce light to efficiently reflect off their polymer mirror no matter what its initial angle of approach.

While the researchers are reporting their results for the first time in the upcoming Science paper, 3M has begun to commercialize several applications that use these nifty new mirrors. For example, these materials have proven to be extremely effective at "piping" visible light over great distances without affecting its color or intensity. Researchers have also used a similar approach to create mirrors that only reflect certain wavelengths and that improve reflective polarizers, making the screens on hand-held computers and laptops much brighter and easier to read.


Story Source:

The above story is based on materials provided by American Association For The Advancement Of Science. Note: Materials may be edited for content and length.


Cite This Page:

American Association For The Advancement Of Science. "Polymer-Based Mirror Outshines All Others." ScienceDaily. ScienceDaily, 5 April 2000. <www.sciencedaily.com/releases/2000/04/000404205617.htm>.
American Association For The Advancement Of Science. (2000, April 5). Polymer-Based Mirror Outshines All Others. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2000/04/000404205617.htm
American Association For The Advancement Of Science. "Polymer-Based Mirror Outshines All Others." ScienceDaily. www.sciencedaily.com/releases/2000/04/000404205617.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins