Featured Research

from universities, journals, and other organizations

Physicists Make Crystal-Liquid Interface Visible For First Time

Date:
August 17, 2009
Source:
Emory University
Summary:
Researchers have captured the first images of what's actually happening in the fuzzy area of the crystal-liquid interface. Their lab's data make the waves between the two states of matter, solid and liquid, visible for the first time.

This is an image of what's actually happening in the fuzzy area of the crystal/liquid interface.
Credit: Eric Weeks Lab/Emory University

"Imagine you're a water molecule in a glass of ice water, and you're floating right on the boundary of the ice and the water," proposes Emory University physicist Eric Weeks. "So how do you know if you're a solid or a liquid?"

Weeks' lab recently captured the first images of what's actually happening in this fuzzy area of the crystal/liquid interface. The lab's data, published this week in the Proceedings of the National Academy of Sciences (PNAS), make the waves between the two states of matter visible for the first time.

"The theory that surface waves move along the crystal/liquid boundary – the intrinsic interface – dates back to 1965 and is well established," says Weeks, associate professor of physics. "What we've done is found a way to take a picture of the intrinsic interface, measure it, and show how it fluctuates over time."

The visual evidence shows that the fuzzy region between the two states is extremely narrow, Weeks says. "The transition from completely organized to completely disorganized goes very quickly, spatially."

Modeling states of matter

Weeks' lab uses tiny plastic balls, each about the size of a cell nucleus, to model states of matter. Samples of these colloids can be fine-tuned into liquid or crystal states by changing the concentrations of the particles suspended in a solution.

"Water molecules are too small too study while they are fluctuating," Weeks explains. "We used the plastic spheres to resize an experiment to a scale that we could observe. You lose some of the detail when you do this, but you hope it's not the critical detail."

The experiment took a great deal of trial and error, says Jessica Hernαndez-Guzmαn, a graduate student in physics and the lead author of the PNAS article. "I was looking for that transition," she says. "I knew what the colloids looked like in a crystal state, and I knew what they looked like as a liquid, but I didn't know what they looked like in-between. When I finally saw (the transition), I felt like I had won the lottery."

The samples of plastic spheres were confined in wedge-shaped glass slides and loaded onto a confocal microscope turned sideways, so that gravity gradually changed the concentration gradient. Rapid, three-dimensional digital scans were made to record the Brownian motion of the particles over one hour. Algorithms were applied to the images to classify the degree of organization of each of the particles. The particles were then digitally colored: from dark blue for the most crystalline, to dark red for the most liquid. The series of images were stitched together and speeded up, becoming microscopy movies that reveal the action along the crystal/liquid interface.

'The zone of confusion'

"You can watch as the boundary fluctuates," Weeks says. "The yellow area along the bumpy line is liquid, but almost crystal. The light blue area is crystal, but almost liquid. The zone of confusion is less than two particles thick. By looking at the tiniest scale possible, we can see that the fuzzy region between the two areas is much smaller than we previously thought."

The research was funded by the National Science Foundation Faculty Early Career Development (CAREER) Program. Better understanding of the crystal/liquid interface could have industrial applications, such as investigating the use of colloidal crystals as optical switches, Weeks says.

Weeks is used to working in fuzzy territory. He has devoted most of his career to probing the mysteries of substances that cannot be pinned down as a solid, liquid or gas. Referred to as "soft condensed materials," they include everyday substances such as toothpaste, peanut butter, shaving cream, plastic and glass.


Story Source:

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


Cite This Page:

Emory University. "Physicists Make Crystal-Liquid Interface Visible For First Time." ScienceDaily. ScienceDaily, 17 August 2009. <www.sciencedaily.com/releases/2009/08/090811091828.htm>.
Emory University. (2009, August 17). Physicists Make Crystal-Liquid Interface Visible For First Time. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2009/08/090811091828.htm
Emory University. "Physicists Make Crystal-Liquid Interface Visible For First Time." ScienceDaily. www.sciencedaily.com/releases/2009/08/090811091828.htm (accessed August 1, 2014).

Share This




More Matter & Energy News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) — British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) — Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) — A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) — Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
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