Featured Research

from universities, journals, and other organizations

Microscopic Cracks Spoil The Transparency Of Glass, Nano-Researchers Find

Date:
October 13, 2003
Source:
Lehigh University
Summary:
A fundamental discovery about the behavior of cooling glass could have a significant impact on the glass- and plastic-making industries, say researchers at Lehigh University. Himanshu Jain, Diamond chair and professor of materials science and engineering at Lehigh, says the breakthrough was made possible by a combination of nanoscopic science and an old-fashioned kitchen recipe.

A fundamental discovery about the behavior of cooling glass could have a significant impact on the glass- and plastic-making industries, say researchers at Lehigh University.

Himanshu Jain, Diamond chair and professor of materials science and engineering at Lehigh, says the breakthrough was made possible by a combination of nanoscopic science and an old-fashioned kitchen recipe.

When molten glass is blown rapidly to make articles of desired shape, Jain's group found, its outermost surface, measuring a few nanometers in thickness, sustains microscopic fractures when it comes into contact with air. One nanometer equals one one-billionth of a meter.

These fractures are microns or nanometers in width and thus too small to be seen with the unaided eye, says Jain. But when they are exposed to an aggressive solution, such as a dishwashing soap, the cracks etch out, spread and begin to dissolve faster than the rest of the glass, leaving behind a dirty look that can not be cleaned away.

In reality, says Jain, the dirty look is merely light that is scattered by the numerous microscopic cracks.

Jain's group described their findings in an article titled "Inhomogeneous evolution of a glass surface via free, rapid expansion" in the Oct. 6, 2003, issue of Applied Physics Letters.

Previously, says Jain, scientists and glass-makers had assumed that under force molten glass expanded in a uniform manner and that finished glass was a chemically durable, homogeneous material.

Jain has spent more than two decades studying the unorganized arrangements and unpredictable movements of atoms in glass's non-crystalline structure.

Several years ago, he was asked by Unilever to figure out why, after being washed in a dishwasher, some wineglasses acquire a lined, milky look that can not be removed by further cleanings.

To solve the puzzle, Jain, his graduate student Anju Sharma, and Unilever collaborator Joseph O. Carnali, turned the prevailing assumptions about the properties of glass on their head and hypothesized that the surface of molten glass was solid and thus prone to cracking.

"We had to come up with a hypothesis because, using the traditional assumption that the surface was behaving like a liquid, we could not understand everything about the corrosion of the glass," he said.

With help from his 12-year-old daughter, Isha, Jain designed a home experiment to test his hypothesis.

The Jains started their experiment with a cooking pot. Using an Internet recipe for making hard candy, known by scientists as sucrose glass, they boiled a mixture of water and sugar, which mimics the molecular behavior of the soda and silica that are the main ingredients of commercial glassware.

When the hot syrup reached the consistency of viscous glass, Jain and his daughter used an empty ballpoint pen to simulate the blowing of glass.

When they studied the microstructure of the sucrose glass surface in detail, the Jains found tiny cracks, indicating that the surface had expanded not in a uniform fashion, like a liquid would, but in a non-uniform manner, as a solid would.

Encouraged by this initial observation, the Lehigh researchers conducted more sophisticated experiments in laboratory, blowing real glass and characterizing its expanding surface with electron microscopy.

"No one had imagined that the top nanometer or two of the surface was a solid," Jain said. "Our lab experiments had proved our hypothesis. Only the top of the surface fractured; the rest of the glass remained very homogeneous."

One factor contributing to the formation of the tiny cracks on the nano-surface, says Jain, is the fact that there is a very high temperature gradient at the glass surface.

Jain conducted his experiments using sucrose glass and real glass, but he believes plastics will behave similarly, although to a lesser degree, as plastic products are formed at lower temperatures.

"This is a quality-control issue for manufacturers," he said. "For nano-researchers, the lack of homogeneity on the nano-scale could be a serious problem that would need to be resolved as nanotechnology enters the market place."

A second paper by Jain and his colleagues, which describes the effect of manufacturing-induced corrosion on wineglasses and other commercial glassware, is scheduled to be published next week by the Journal of the American Ceramics Society.


Story Source:

The above story is based on materials provided by Lehigh University. Note: Materials may be edited for content and length.


Cite This Page:

Lehigh University. "Microscopic Cracks Spoil The Transparency Of Glass, Nano-Researchers Find." ScienceDaily. ScienceDaily, 13 October 2003. <www.sciencedaily.com/releases/2003/10/031013000919.htm>.
Lehigh University. (2003, October 13). Microscopic Cracks Spoil The Transparency Of Glass, Nano-Researchers Find. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2003/10/031013000919.htm
Lehigh University. "Microscopic Cracks Spoil The Transparency Of Glass, Nano-Researchers Find." ScienceDaily. www.sciencedaily.com/releases/2003/10/031013000919.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Robotic Eyes' Helps Japan's Bipedal Bot Run Faster

'Robotic Eyes' Helps Japan's Bipedal Bot Run Faster

Reuters - Innovations Video Online (Oct. 16, 2014) Japanese researcher uses an eye-sensor camera to enable a bipedal robot to balance itself, while running on a treadmill. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Lockheed Martin's Fusion Concept Basically An Advertisement

Lockheed Martin's Fusion Concept Basically An Advertisement

Newsy (Oct. 15, 2014) Lockheed Martin announced plans to develop the first-ever compact nuclear fusion reactor. But some experts said the excitement is a little premature. Video provided by Newsy
Powered by NewsLook.com
First Confirmed Case Of Google Glass Addiction

First Confirmed Case Of Google Glass Addiction

Buzz60 (Oct. 15, 2014) A Google Glass user was treated for Internet Addiction Disorder caused from overuse of the device. Morgan Manousos (@MorganManousos) has the details on how many hours he spent wearing the glasses, and what his symptoms were. Video provided by Buzz60
Powered by NewsLook.com
Science Proves Why Pizza Is So Delicious

Science Proves Why Pizza Is So Delicious

Buzz60 (Oct. 15, 2014) The American Chemical Society’s latest video about chemistry in every day life breaks down pizza, and explains exactly why it's so delicious. Gillian Pensavalle (@GillianWithaG) has the video. Video provided by Buzz60
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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