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 July 24, 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 July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) 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