(Press-News.org) University of Waterloo physicists have succeeded in measuring how the surfaces of glassy materials flow like a liquid, even when they should be solid.
A series of simple and elegant experiments were the solution to a problem that has been plaguing condensed matter physicists for the past 20 years.
Understanding the mobility of glassy surfaces has implications for the design and manufacture of thin-film coatings and also sets practical limits on how small we can make nanoscale devices and circuitry.
The work is the culmination of a project carried out by a research team led by Professor James Forrest and doctoral student Yu Chai from the University of Waterloo as well as researchers from École Superieure de Physique et de Chimie Industrielles in France and McMaster University.
Their groundbreaking work was published in the prestigious scientific journal, Science, this week.
"Glasses are fascinating materials. At low temperatures they're solid, and at higher temperatures they're liquid. At intermediate temperatures, it's hard to consider them as only one or the other," said Professor Forrest. "Surfaces of glassy polymers shouldn't flow below the glass transition temperature, but they do. The question is why."
Glass is much more than the material in bottles and windows. In fact, any solid without an ordered, crystalline structure is considered a glassy material, so metals, small molecules, and polymers can all be made into glassy materials.
Polymers, the building block of all plastics, are almost always glassy rather than crystalline. These materials undergo a transition between a brittle solid and a molten liquid in a narrow temperature range, which encompasses the so-called glass transition temperature.
In a series of experiments, Forrest and colleagues started with very thin slices of polystyrene stacked to create tiny staircase-like steps about 100-nanometres high – less than 0.001 per cent the thickness of a human hair. They then measured these steps as they became shorter, wider and less defined over time.
Graph showing how the top surface of a glassy polymer moves like a liquid.Graph showing how the top surface of a glassy polymer moves like a liquid
The simple 2-dimensional profile of this surface step allowed the physicists to numerically model the changes to the surface's geometry above and below the glass transition temperature.
Results show that above the transition temperature, polystyrene flows entirely like a liquid; but below this temperature the polymer becomes a solid with a thin liquid-like layer at the surface.
Being able to calculate how these nanostructures may evolve over time and under what conditions will bring engineers a step further towards making nanotechnology an everyday reality.
Professor Forrest and doctoral student Yu Chai are from the Department of Physics and Astronomy in the Faculty of Science. Forrest is also a University Research Chair, a member of the Waterloo Institute for Nanotechnology and an associate faculty member at the Perimeter Institute.
The project team also includes Kari Dalnoki-Veress and J.D. McGraw from McMaster University and Thomas Salez, Michael Benzaquen and Elie Raphael of the École Superieure de Physique et de Chimie Industrielles in Paris.
Waterloo physicists solve 20-year-old debate surrounding glassy surfaces
Nano-thin layers of coffee cup reveal how the surface of glass flows like liquid
ELSE PRESS RELEASES FROM THIS DATE:
Burmese pythons pose little risk to people in Everglades
EVERGLADES NATIONAL PARK, Fla. -- The estimated tens of thousands of Burmese pythons now populating the Everglades present a low risk to people in the park, according to a new assessment by U.S. Geological Survey and National Park Service scientists. The human risk assessment looked at five incidents that involved humans and Burmese pythons over a 10-year period in Everglades National Park. All five incidents involved pythons striking at biologists who were conducting research in flooded wetlands. "Visitor and staff safety is always our highest priority at Everglades ...
Kessler Foundation researchers find education attenuates impact of TBI on cognition
West Orange, NJ. February 28, 2014. Kessler Foundation researchers have found that higher educational attainment (a proxy of intellectual enrichment) attenuates the negative impact of traumatic brain injury (TBI) on cognitive status. The brief report, Sumowski J, Chiaravalloti N, Krch D, Paxton J, DeLuca J. Education attenuates the negative impact of traumatic brain injury (TBI) on cognitive status, was published in the December issue of Archives of Physical Medicine & Rehabilitation Vol. 94, Issue 12:2562-64. Cognitive outcomes vary post-TBI, even among individuals ...
American Journal of Transplantation reports REGiMMUNE's transplant tolerance results
Tokyo, Japan – February 28, 2014 – REGiMMUNE Corporation announced that the American Journal of Transplantation (AJT) has published its paper that describes a novel approach to long-term tolerance in organ transplantation with continuous administration of immune suppressants. "A Novel Approach Inducing Transplant Tolerance by Activated Invariant Natural Killer T Cells with Costimulatory Blockade" was published in the AJT March 2014 Issue 3, Volume 14, pages 554-567, and was first made available online as an early view on February 6, 2014. Robust, lifelong, donor-specific ...
Study: Racial bias in pain perception appears among children as young as 7
A new University of Virginia psychology study has found that a sample of mostly white American children – as young as 7, and particularly by age 10 – report that black children feel less pain than white children. The study, which builds on previous research on bias among adults involving pain perception, is published in the Feb. 28 issue of the British Journal of Developmental Psychology. "Our research shows that a potentially very harmful bias in adults emerges during middle childhood, and appears to develop across childhood," said the study's lead investigator, Rebecca ...
BNI study reveal unexpected findings
(Phoenix , Ariz. Feb 28, 2014) -- "The results of this study are counter to most expectations," said Dr. Brachman, Director of Radiation Oncology at Barrow and St. Joseph's. "Bevacizuman had been shown in earlier studies to be an effective drug in the treatment of patients with recurrent disease. But, on newly diagnosed patients, it did not, in fact, prolong survival." The randomized, double-blind placebo controlled trial of 621 adults was funded by the National Cancer Institute and the drug manufacturer Genentech from 2009 to2012. Glioblastoma is the most common primary ...
Northern Sumatra dealing with smoke from fires
On February 27, 2014, the Wall Street Journal and Southeast Asia Realtime reported that: "the plantation-rich province of Riau on Indonesia's Sumatra Island has declared a state of emergency as fires set for land clearing have sent pollution levels soaring and smoke made breathing difficult for thousands." Tens of thousands of Riau residents are suffering from the effects of the smoke coming from dozens of fires set to clear land in Sumatra. Riau is the center of Indonesia's more than $20 billion palm oil industry—the world's largest. Fires occur with frequency in Riau ...
Food production in the northeastern US may need to change if climate does
BOSTON (February 28, 2014) — If significant climate change occurs in the United States it may be necessary to change where certain foods are produced in order to meet consumer demand. In a paper published online this week in the journal Renewable Agriculture and Food Systems, researchers at the Friedman School of Nutrition Science and Policy at Tufts University provide an overview of current farmland use and food production in the Northeastern U.S., identifying potential vulnerabilities of the 12-state region*. Led by Tim Griffin, Ph.D., associate professor and director ...
Psychiatric nursing specialists played key role in response to Boston Marathon bombing
Philadelphia, Pa. (February 28, 2014) – Psychiatric advanced practice nurses (APNs) played a critical role in supporting psychological recovery after the Boston Marathon bombing—not only for injured patients, but also for family members and hospital staff, according to an article in Clinical Nurse Specialist, official journal of the the National Association of Clinical Nurse Specialists. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health. Barbara Lakatos, DNP, PMHCNS-BC, and colleagues of the Psychiatric Nursing Resource Service ...
Shaky hand, stable spoon: U-M study shows device helps essential tremor patients
ANN ARBOR, Mich. — For people whose hands shake uncontrollably due to a medical condition, just eating can be a frustrating and embarrassing ordeal – enough to keep them from sharing a meal with others. But a small new study conducted at the University of Michigan Health System suggests that a new handheld electronic device can help such patients overcome the hand shakes caused by essential tremor, the most common movement disorder. In a clinical trial involving 15 adults with moderate essential tremor, the device improved patients' ability to hold a spoon still enough ...
A molecular ballet under the X-ray laser
An international team of researchers has used the world's most powerful X-ray laser to take snapshots of free molecules. The research team headed by Prof. Jochen Küpper of the Hamburg Center for Free-Electron Laser Science (CFEL) choreographed a kind of molecular ballet in the X-ray beam. With this work, the researchers have cleared important hurdles on the way to X-ray images of individual molecules, as they explain in the scientific journal Physical Review Letters. CFEL is a cooperation of DESY, the University of Hamburg, and the Max Planck Society. "We have captured ...
LAST 30 PRESS RELEASES:
Scientists model 'true prevalence' of COVID-19 throughout pandemic
New breakthrough to help immune systems in the fight against cancer
Through the thin-film glass, researchers spot a new liquid phase
Administering opioids to pregnant mice alters behavior and gene expression in offspring
Brain's 'memory center' needed to recognize image sequences but not single sights
Safety of second dose of mRNA COVID-19 vaccines after first-dose allergic reactions
Changes in disparities in access to care, health after Medicare eligibility
Use of high-risk medications among lonely older adults
65+ and lonely? Don't talk to your doctor about another prescription
Exosome formulation developed to deliver antibodies for choroidal neovascularization therapy
Second COVID-19 mRNA vaccine dose found safe following allergic reactions to first dose
Plant root-associated bacteria preferentially colonize their native host-plant roots
Rare inherited variants in previously unsuspected genes may confer significant risk for autism
International experts call for a unified public health response to NAFLD and NASH epidemic
International collaboration of scientists rewrite the rulebook of flowering plant genetics
Improving air quality reduces dementia risk, multiple studies suggest
Misplaced trust: When trust in science fosters pseudoscience
Two types of blood pressure meds prevent heart events equally, but side effects differ
New statement provides path to include ethnicity, ancestry, race in genomic research
Among effective antihypertensive drugs, less popular choice is slightly safer
Juicy past of favorite Okinawan fruit revealed
Anticipate a resurgence of respiratory viruses in young children
Anxiety, depression, burnout rising as college students prepare to return to campus
Goal-setting and positive parent-child relationships reduce risk of youth vaping
New research identifies cancer types with little survival improvements in adolescents and young adul
Oncotarget: Replication-stress sensitivity in breast cancer cells
Oncotarget: TERT and its binding protein: overexpression of GABPA/B in gliomas
Development of a novel technology to check body temperature with smartphone camera
The mechanics of puncture finally explained
Extreme heat, dry summers main cause of tree death in Colorado's subalpine forests[Press-News.org] Waterloo physicists solve 20-year-old debate surrounding glassy surfaces
Nano-thin layers of coffee cup reveal how the surface of glass flows like liquid