PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Expanding the degrees of surface freezing

Molecular ordering phenomenon found at interface between complex liquids and solids

2011-04-02
(Press-News.org) UPTON, NY — As part of the quest to form perfectly smooth single-molecule layers of materials for advanced energy, electronic, and medical devices, researchers at the U.S. Department of Energy's Brookhaven National Laboratory have discovered that the molecules in thin films remain frozen at a temperature where the bulk material is molten. Thin molecular films have a range of applications extending from organic solar cells to biosensors, and understanding the fundamental aspects of these films could lead to improved devices.

The study, which appears in the April 1, 2011, edition of Physical Review Letters, is the first to directly observe "surface freezing" at the buried interface between bulk liquids and solid surfaces.

"In most materials, you expect that the surface will start to disorder and eventually melt at a temperature where the bulk remains solid," said Brookhaven physicist Ben Ocko, who collaborated on the research with scientists from the European Synchrotron Radiation Facility (ESRF), in France, and Bar-Ilan University, in Israel. "This is because the molecules on the outside are less confined than those packed in the deeper layers and much more able to move around. But surface freezing contradicts this basic idea. In surface freezing, the interfacial layers freeze before the bulk."

In the early 1990s, two independent teams (one at Brookhaven) made the first observation of surface freezing at the vapor interface of bulk alkanes, organic molecules similar to those in candle wax that contain only carbon and hydrogen atoms. Surface freezing has since been observed in a range of simple chain molecules and at various interfaces between them.

"The mechanics of surface freezing are still a mystery," said Bar Ilan scientist Moshe Deutsch. "It's puzzling why alkanes and their derivatives show this unusual effect, while virtually all other materials exhibit the opposite, surface melting, effect."

In the most recent study, the researchers discovered that surface freezing also occurs at the interface between a liquid and a solid surface. In a temperature-controlled environment at Brookhaven's National Synchrotron Light Source and the ESRF, the group made contact between a piece of highly polished sapphire and a puddle of liquid alkanol — a long-chain alcohol. The researchers shot a beam of high-intensity x-rays through the interface and by measuring how the x-rays reflected off the sample, the group revealed that the alkanol molecules at the sapphire surface behave very differently from those in the bulk liquid.

According to ESRF scientist Diego Pontoni, "Surprisingly, the alkanol molecules form a perfect frozen monolayer at the sapphire interface at temperatures where the bulk is still liquid." At sufficiently high temperatures, about 30 degrees Celsius above the melting temperature of the bulk alkanol, the monolayer also melts.

The temperature range over which this frozen monolayer exists is about 10 times greater than what's observed at the liquid-vapor interfaces of similar materials. According to Alexei Tkachenko, a theoretical physicist who works at Brookhaven's Center for Functional Nanomaterials , "The temperature range of the surface-frozen layer and its temperature-dependent thickness can be described by a very simple model that we developed. What is remarkable is that the surface layer does not freeze abruptly as in the case of ice, or any other crystal. Rather, a smooth transition occurs over a temperature range of several degrees."

Said Ocko, "These films are better ordered and smoother than all other organic monolayer films created to date."

Moshe Deutsch added, "The results of this study and the theoretical framework which it provides may lead to new ideas on how to make defect-free, single molecule-thick films."

### Funding for this work was provided by the U.S. Department of Energy's Office of Science and the U.S.-Israel Binational Science Foundation.

The Center for Functional Nanomaterials at Brookhaven National Laboratory is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://nano.energy.gov .

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation of State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

Visit Brookhaven Lab's electronic newsroom for links, news archives, graphics, and more at http://www.bnl.gov/newsroom , or follow Brookhaven Lab on Twitter, http://twitter.com/BrookhavenLab .


ELSE PRESS RELEASES FROM THIS DATE:

4imprint UK's Helping Hand Programme, '300 Bags Full'

2011-04-02
PRIME is the only charity in the UK aimed at helping older people to set up their own business as a way of getting back to work. Established by Prince Charles as a sister charity to The Prince's Trust, PRIME helps the growing number of people in the 50+ age group who need to continue working, or get back into work after losing their job, by helping them to set up their own businesses. "Being a small charity, we don't have the resources to do everything we'd like to do," confirms Ian Stobie, Marketing and PR Manager for PRIME. "We have a huge amount of useful material on ...

New tool makes programs more efficient without sacrificing safety functions

2011-04-02
Computer programs are incorporating more and more safety features to protect users, but those features can also slow the programs down by 1,000 percent or more. Researchers at North Carolina State University have developed a software tool that helps these programs run much more efficiently without sacrificing their safety features. "These safety features – or meta-functions – can slow a program down so much that software developers will often leave them out entirely," says Dr. James Tuck, an assistant professor of electrical and computer engineering at NC State and leader ...

Micro-RNA blocks the effect of insulin in obesity

2011-04-02
This release is available in German. Body weight influences the risk of developing diabetes: between 80 and 90 percent of patients with type 2 diabetes are overweight or obese. According to scientists at the Max Planck Institute for Neurological Research in Cologne and the Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases (CECAD), short ribonucleic acid molecules, known as micro-RNAs, appear to play an important role in this mechanism. The researchers discovered that the obese mice form increased levels of the regulatory RNA molecule ...

The Prestigious University of Deusto Introduces the AuraPortal Learning System into its Teaching Activities

2011-04-02
AuraPortal (www.auraportal.com), a global provider of Business Process Management (BPM), has announced today that the University of Deusto has signed a cooperation agreement with the company AURA, owner of the AuraPortal Learning System, in which AURA provides Deusto with a software tool for its use in educational activities in order to introduce and develop educational and research programs for BPM technologies. Currently, the AuraPortal BPM Suite is being used by the UTIC (Technical Unit for Innovation and Quality) for the implementation of quality processes in colleges. ...

New strategic plan for NIH obesity research seeks to curb epidemic

2011-04-02
To combat the obesity epidemic, the National Institutes of Health is encouraging diverse scientific investigations through a new Strategic Plan for NIH Obesity Research. More than one-third of adults in the United States and nearly 17 percent of the nation's children are now obese, which increases a person's chance of developing many health problems, including type 2 diabetes, heart disease, high blood pressure, fatty liver disease, and some cancers. In 2008, obesity-related medical costs were an estimated $147 billion. Government, nonprofit and community groups, businesses, ...

Researchers need to engage lesbian, gay, bisexual, and transginder populations in health studies

2011-04-02
WASHINGTON — Researchers need to proactively engage lesbian, gay, bisexual, and transgender people in health studies and collect data on these populations to identify and better understand health conditions that affect them, says a new report from the Institute of Medicine. The scarcity of research yields an incomplete picture of LGBT health status and needs, which is further fragmented by the tendency to treat sexual and gender minorities as a single homogeneous group, said the committee that wrote the report. The report provides a thorough compilation of what is ...

Sale Fever at Designer Shoe E-Tailer KindredSole.com

2011-04-02
KindredSole.com has announced that on 1st April between 6am and 1pm it will be having its first ever flash shoes sale. It might be April fools but this is no joke, its KindredSole.com shoe sale extravaganza! KindredSole.com flash sale will include designer brands from J Shoes to Bronx Shoes with savings of up to 50% off. A surge in customers are expected to form an orderly online queue following an online promotion through loyal customers and social media campaigns on Twitter and Facebook. Visitors to Kindred Sole will be able to access the sale through the following KindredSole.com ...

Good vibrations?

2011-04-02
This press release is available in French.Montreal, March 31, 2011 – Anyone who's ever used an electric or gas lawnmower knows how pushing the device can cause tingling hands. This side-effect is caused by motor vibrations and comes with the turf for people who cut grass for a living. Workers who employ handheld power tools in the mining, forestry, manufacturing and services sectors can also be exposed to large levels of vibrations in their hands and upper arms. Such vibrations are not without consequence. "Prolonged exposure to intensive tool vibration can cause ...

Getting closer to a better biocontrol for garden pests

2011-04-02
This release is available in Spanish. U.S. Department of Agriculture (USDA) scientists have found strains of bacteria that could one day be used as environmentally friendly treatments to keep caterpillars and other pests out of gardens and cultivated fields. Researchers with the USDA's Agricultural Research Service (ARS) surveyed the agency's bacterial collection and discovered that strains sharing the ability to produce a particular enzyme survive being fed to caterpillars longer than those that don't. Such survivability makes them better candidates for controlling ...

TakeCare to Provide Screening of "Palz" For TeenPalz.com

2011-04-02
TakeCare, a provider of online personality and risk assessments and TeenPalz.com, which offers virtual supervision, support and activities for the millions of teens home alone, have agreed to offer NannyTest as screening tool for virtual "Palz". NannyTest is an online personality test that helps parents screen potential caregivers. It is unique in combining both risk assessment and personal traits assessment. The test provides better insight into the personality and traits of the caregiver, and ensures parents that they have done the best they can to leave their kids ...

LAST 30 PRESS RELEASES:

Twelve questions to ask your doctor for better brain health in the new year

Microelectronics Science Research Centers to lead charge on next-generation designs and prototypes

Study identifies genetic cause for yellow nail syndrome

New drug to prevent migraine may start working right away

Good news for people with MS: COVID-19 infection not tied to worsening symptoms

Department of Energy announces $179 million for Microelectronics Science Research Centers

Human-related activities continue to threaten global climate and productivity

Public shows greater acceptance of RSV vaccine as vaccine hesitancy appears to have plateaued

Unraveling the power and influence of language

Gene editing tool reduces Alzheimer’s plaque precursor in mice

TNF inhibitors prevent complications in kids with Crohn's disease, recommended as first-line therapies

Twisted Edison: Bright, elliptically polarized incandescent light

Structural cell protein also directly regulates gene transcription

Breaking boundaries: Researchers isolate quantum coherence in classical light systems

Brain map clarifies neuronal connectivity behind motor function

Researchers find compromised indoor air in homes following Marshall Fire

Months after Colorado's Marshall Fire, residents of surviving homes reported health symptoms, poor air quality

Identification of chemical constituents and blood-absorbed components of Shenqi Fuzheng extract based on UPLC-triple-TOF/MS technology

'Glass fences' hinder Japanese female faculty in international research, study finds

Vector winds forecast by numerical weather prediction models still in need of optimization

New research identifies key cellular mechanism driving Alzheimer’s disease

Trends in buprenorphine dispensing among adolescents and young adults in the US

Emergency department physicians vary widely in their likelihood of hospitalizing a patient, even within the same facility

Firearm and motor vehicle pediatric deaths— intersections of age, sex, race, and ethnicity

Association of state cannabis legalization with cannabis use disorder and cannabis poisoning

Gestational hypertension, preeclampsia, and eclampsia and future neurological disorders

Adoption of “hospital-at-home” programs remains concentrated among larger, urban, not-for-profit and academic hospitals

Unlocking the mysteries of the human gut

High-quality nanodiamonds for bioimaging and quantum sensing applications

New clinical practice guideline on the process for diagnosing Alzheimer’s disease or a related form of cognitive impairment or dementia

[Press-News.org] Expanding the degrees of surface freezing
Molecular ordering phenomenon found at interface between complex liquids and solids