(Press-News.org) A team of researchers from the University of Leicester and France's G2ELab-CNRS in Grenoble have for the first time observed the growth of free nanoparticles in helium gas in a process similar to the decaffeination of coffee, providing new insights into the structure of nanoparticles.
Nanoparticles have a very large surface area compared with their volume and are often able to react very quickly. This makes them useful as catalysts in chemical reactions and they are often used in sports equipment, clothing and sunscreens.
In a paper published by the Journal of Physical Chemistry Letters and funded by the Royal Society, The Leverhulme Trust, the British Council and CONACYT, the teams from the University of Leicester's Department of Physics and Astronomy and the CNRS in Grenoble measured how helium ions cluster with neutral helium atoms and grow into nanoparticles.
During the study they examined how helium ions drift through a cell filled with helium atoms. When the pressure of helium was increased the researchers observed a decrease in the mobility of the ions.
Dr Klaus von Haeften from the University of Leicester's Department of Physics and Astronomy, who has received a Visiting Professorship from the University Joseph Fourier, said: "We concluded that the increased pressure forced more and more helium atoms to bind to the ions gradually, until the clusters grew to nanometre-sized particles. This process continued until the nanoparticles reached the maximum size possible which also depended on the temperature.
"Further increase of the pressure was found to reduce the size, which we interpreted as compression. These size changes could then be followed in great detail. For low and moderate pressures the size changed rather rapidly whereas in the high pressure region the changes were slow."
By analysing how quickly the particle volume changed with pressure the researchers were able to investigate the structure of the nanoparticles.
Nelly Bonifaci from the G2ELab-CNRS said: "At low and moderate pressure the nanoparticles were much softer than solid helium and we concluded that they must be liquid. At high pressures they became progressively harder and eventually solid."
Dr von Haeften added: "By choosing helium we were able to study a system of greatest possible purity and our results are therefore very precise. Similar processes occur in the decaffeination of coffee in high pressure carbon dioxide, in dry cleaning and in chemical manufacturing. In all these processes nanoparticles grow. By knowing their size we can much better understand these processes and improve them."
This is the first time that researchers have been able to observe the growth of free nanoparticles in a large range of pressure in gaseous helium.
Frédéric Aitken from the G2ELab-CNRS added: "Our work is an important benchmark for the research on the formation and size of nanoparticles."
INFORMATION:
The original article 'Formation of Positively Charged Liquid Helium Clusters in Supercritical Helium and their Solidification upon Compression' has appeared in the Journal of Physical Chemistry Letters and is available at http://dx.doi.org/10.1021/acs.jpclett.5b01159
Notes to editors:
For more information please contact Dr Klaus von Haeften on kvh6@leicester.ac.uk
About the Leverhulme Trust:
The Leverhulme Trust was established by the Will of William Hesketh Lever, the founder of Lever Brothers. Since 1925 the Trust has provided grants and scholarships for research and education; today it is one of the largest all-subject providers of research funding in the UK, distributing approximately £80 million a year. For more information: http://www.leverhulme.ac.uk @LeverhulmeTrust
About the British Council
The British Council is the UK's international organisation for cultural relations and educational opportunities. We create international opportunities for the people of the UK and other countries and build trust between them worldwide.
We work in more than 100 countries and our 8,000 staff - including 2,000 teachers - work with thousands of professionals and policy makers and millions of young people every year by teaching English, sharing the arts and delivering education and society programmes.
We are a UK charity governed by Royal Charter. A core publicly-funded grant provides 20 per cent of our turnover which last year was £864 million. The rest of our revenues are earned from services which customers around the world pay for, such as English classes and taking UK examinations, and also through education and development contracts and from partnerships with public and private organisations. All our work is in pursuit of our charitable purpose and supports prosperity and security for the UK and globally.
For more information, please visit: http://www.britishcouncil.org. You can also keep in touch with the British Council through http://twitter.com/britishcouncil and http://blog.britishcouncil.org/.
Contact between children and fathers following parental separation facilitates the continued abuse of women and children, according to new research focusing on the experiences of families with a prior history of domestic abuse conducted by social work experts at Trinity College Dublin.
The research, which explored the experiences of post-separation fathering in families with prior history of domestic abuse perpetrated by the father against the mother, involved the completion of survey questionnaires 219 mothers regarding their 449 children as well as face-to-face interviews ...
TAMPA, Fla. - Recent advances in the understanding of cancer have led to more personalized therapies, such as drugs that target particular proteins and tests that analyze gene expression patterns in tumors to predict a patient's response to therapy. Moffitt Cancer Center researchers have contributed to these advances by developing the first test that analyzes the sensitivity of tumors to radiation therapy. They discovered that colon cancer metastases have varying sensitivity to radiation therapy based on their anatomic location.
Researchers from Moffitt previously developed ...
An algorithm dubbed ENVE could be the Google for genetic aberrations -- and it comes from Case Western Reserve.
Remember the World Wide Web before the famed search engine? The web offered extraordinary amounts of information, but no consistently reliable way to secure relevant results.
Cancer researchers at Case Western Reserve encountered a comparable conundrum when considering reams of data about the body that new technological advances provide -- how could they tell what parts of the information actually offer value. In this instance, the goal was to distinguish ...
This news release is available in German.
Organic molecules allow producing printable electronics and solar cells with extraordinary properties. In spintronics, too, molecules open up the unexpected possibility of controlling the magnetism of materials and, thus, the spin of the flowing electrons. According to what is reported in Nature Materials by a German-French team of researchers, a thin layer of organic molecules can stabilize the magnetic orientation of a cobalt surface. (DOI: 10.1038/NMAT4361)
"This special interaction between organic molecules and metal ...
Reintroducing a species into an area where it has vanished can be a great tool for conservation, but for reintroduction to be successful it's crucial to understand how the habitat has changed in the interim and whether the reintroduced species will be able to thrive in its former home. Extirpated in the 1960s as a result of human activity, Bald Eagles (Haleiaeetus leucocephalus) have been reintroduced to California's Channel Islands over the last 35 years. A study published this week in The Condor: Ornithological Applications examined the diets of these reestablished eagles ...
People who grew up in a working class family are more satisfied in later life than those from a higher class background according to new research from The University of Manchester.
The study by Dr Bram Vanhoutte and Professor James Nazroo, published in the Journal of Population Ageing, also found that English people who climb the social ladder are more content and happy when they get older than people in the States who are similarly upwardly mobile.
The research sought to find out whether social mobility makes people happier in later life while taking into account ...
Investigators affiliated with VIB and UGent recently achieved great success with a study involving biomedical research on mouse models. The research group of Prof Peter Vandenabeele (VIB/UGent) recently used tangible examples to demonstrate how the side effects of genetic modification of mice can complicate the interpretation of biomedical research. The team developed a web tool that allows scientists to estimate the impact of this phenomenon more accurately. Their findings were recently published in the medical journal Immunity and received ample attention by a preview ...
Mangrove forests could play a crucial role in protecting coastal areas from sea level rise caused by climate change, according to new research involving the University of Southampton.
A joint study between researchers at the University of Southampton along with colleagues from the Universities of Auckland and Waikato in New Zealand used leading-edge mathematical simulations to study how mangrove forests respond to elevated sea levels.
Taking New Zealand mangrove data as the basis of a new modelling system, the team were able to predict what will happen to different types ...
The U.S. Supreme Court's recent ruling legalizing marriage between same-sex couples in all 50 states follows on the heels of national polls showing rapid cultural changes in attitudes toward lesbian and gay people. A new University of Virginia study confirms this, showing that not only are Americans' conscious and unconscious biases against lesbian women and gay men decreasing across all demographic groups, but the trend also appears to be accelerating.
"Many people have this gut feeling that our culture has changed," said lead researcher Erin Westgate, a doctoral psychology ...
ROCHESTER, MINN. - A group of 118 of the nation's leading cancer experts have drafted a prescription for reducing the high cost of cancer drugs and voiced support for a patient-based grassroots movement demanding action on the issue. Their recommendations and support are outlined in a commentary, co-authored by the group, in the journal Mayo Clinic Proceedings.
"High cancer drug prices are affecting the care of patients with cancer and our health care system," says lead author Ayalew Tefferi, M.D., a hematologist at Mayo Clinic. "The average gross household income in ...
