B-MRS Newsletter. Year 8, issue 10.


 

20Anos_260px

Newsletter of the
Brazilian Materials
Research Society

Year 8, issue 10. December 3, 2021.

B-MRS elections

– The voting period for the election of the new Executive Board and members of the Deliberative Council is open until December 14th.

– All members who are up to date with their annuity are able to vote.

– Voting will be performed online. To vote, each member must access their personal account on the B-MRS website entering login and password. If the member is up to date with the annual fee, the link to vote will be available on the main page.

Featured paper

A computational study carried out at UFSCar sheds new light on the understanding of fundamental issues of supercooled liquids and glasses, opening perspectives for the production of new vitreous materials. The research was published in Acta Materialia. Know more.

destaque_news

Papers suggested by the community

In an article featured on the cover of Advanced Materials, researchers from CNPEM and UNICAMP report the design and characterization of new ultra-compact platforms of three-dimensional electrochemical organic transistors, in addition to their applications in monitoring the oxidation of dopamine – a biomarker related to neurodegenerative diseases in humans. Access the paper https://doi.org/10.1002/adma.202101518.

Also in a cover article in Advanced Materials, researchers from Embrapa and UFSCar, in collaboration with scientists from abroad, review a very important issue for the circular economy: the production of advanced multifunctional materials (bioplastics) from the recycling of agrifood waste. Access the paper https://doi.org/10.1002/adma.202170342.

XX B-MRS Meeting

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The organizing committee received 33 symposium proposals!

The list of approved symposia will be released by December 20th.

The event will be held in Foz do Iguaçu from 25 to 29 September 2022.

The coordinators are professors Lucimara Stolz Roman (UFPR) and Marcela Mohallen Oliveira (UTFPR).

Event Website: https://www.sbpmat.org.br/20encontro/

Opportunities

– Nominations for awards (lectureships) bestowed by journals of the Royal Society of Chemistry for early-career researchers with contributions in the fields of polymers (see here), biomaterials (see here) and soft matter (see here) are open. Deadline: 12/31/21.

– LNNano – CNPEM has called for research proposals for the use of its electron microscopy equipment. Submission is open until 12/23/21. Know more.

– Postdoctoral opportunities at IPEN and UFABC linked to the Center for Innovation on New Energies (CINE). Applications until 12/25/21. Know more.

News from B-MRS members

Professor Daniel Mario Ugarte (UNICAMP), founding member of B-MRS, was sworn in as a member of TWAS (The World Academy of Sciences) in a virtual ceremony held on November 4th. Know more.

ugarte_news

Reading tips

– Based on copper and nanocellulose, a new thin and flexible material with excellent capacity to conduct ions is promising for safer, more efficient and sustainable batteries than the current ones (Nature). Know more.

– Researchers from the IFGW-UNICAMP and collaborators from abroad study properties and defects of boron nitride monolayers and open possibilities for applying the material as a UVC light source, used to inactivate microorganisms (2D Materials). Know more.

– An article describes a lesser-known aspect of the ever-engaging life story of scientist Mildred Dresselhaus: her unique style of teaching Solid State Physics at MIT and her mentoring work for the (very few) girls who studied Physics at the institution in the 1970s. Know more.

Advocacy

-B-MRS supported the tweet for the defense of the Brazilian post-graduation held on 11/29. Know more.

– B-MRS signed an open letter in defense of the evaluation process of Brazilian postgraduate courses. Know more.

– B-MRS expressed solidarity with the coordinators of the Physics/Astronomy Area of CAPES who resigned. Know more.

– B-MRS supported the tweet for the release of resources for Brazilian science and for the readjustment of scholarships, carried out on 11/23. Know more.

Events

– III Simpósio Brasileiro sobre Maternidade e Ciência. Online. December 6 to 10, 2021. Website.

– 5th International Conference on Applied Surface Science. Palma, Mallorca (Spain). April 25 to 28, 2022. Website.

– 2022 E-MRS Spring Meeting and Exhibit. May 30 to June 3, 2022. Website.

– 4th Workshop on Coated Tools & Multifunctional Thin Films. Campinas, SP (Brazil). July 20 to 23, 2022. Website.

– XVIII International Small Angle Scattering Conference. Campinas, SP (Brazil). September 11 to 16, 2022. Website.

– XX B-MRS Meeting. Foz do Iguaçu, PR (Brazil). September 25 to 29, 2022. Website.

– 11th International Conference of the African Materials Research Society (AMRS2022 ). Dakar (Senegal). December 12 to 15, 2022. Website.

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Featured paper: Solving the paradox of supercooled liquids.


Scientific research carried out at the Brazilian Federal University of São Carlos (UFSCar) sheds new light on supercooled liquids and glasses – two states of matter, in the broadest sense of the expression, which still present many fundamental questions to science. In particular, the work provides strong evidence to solve an old paradox involving supercooled liquids, and opens perspectives for the production of new glassy and crystalline materials.

Supercooled liquids are those that, even at temperatures below the melting point, remain in a liquid state. The best known example is water, which freezes at 0 °C but can be kept as a supercooled liquid even after a few hours in the freezer, as shown in this video.


But not just water, any liquid can be in a supercooled state as long as the conditions that prevent the formation of the first crystal, a phenomenon called nucleation, are met. However, if nucleation does occur, the delicate balance of the supercooled liquid will break down and it will crystallize into a much more stable state. To trigger this process, just waiting for a while is sufficient, stirring the supercooled liquid or introducing a catalyst into it.

In addition to arousing the curiosity of scientists and lay people, supercooled liquids have some applications in situations where it is necessary to lower the temperature to very low levels without causing freezing (crystallization), such as, for example, the preservation of organs donated for transplantation.

In this work, the authors sought to understand the interaction between two phenomena that concur during the crystallization process of supercooled liquids: relaxation (a phenomenon that occurs spontaneously in the amorphous structure of super-cooled liquids on their way to a phase of greater stability) and crystal nucleation. For this, they used atomistic computer simulation tools, that allows describing the position of each atom of a compound as a function of time, to simulate these processes in germanium, whose melting temperature is 938 °C. Above that temperature, germanium crystals “melts”. Below it, if the conditions that prevent the nucleation of crystals are maintained, the liquid germanium does not solidify and remains as a supercooled liquid.

It all started with a paradox

The idea of studying the interaction between nucleation and structural relaxation came from Professor Edgar Dutra Zanotto in 1987, when he was a young professor at UFSCar and coordinated the Vitreous Materials Laboratory, which he had created 10 years before.

It was then that Professor Zanotto began to study the Kauzmann paradox. Published in 1948, this theoretical prediction is named after Walter Kauzmann, who was a professor at Princeton University (USA) and made important contributions to the study of supercooled glasses and liquids. The paradox states that, at a given temperature (called the Kauzmann temperature), the entropy of a supercooled liquid must equal the entropy of the crystalline phase of the same compound. In this context, if cooling continued, the supercooled liquid would end up having zero entropy at a temperature above absolute zero. To avoid this situation, which contradicts the third law of Thermodynamics, supercooled liquids should crystallize before relaxing to the vitreous state, which is a non-crystalline state, above the Kauzmann temperature.

- The authors of the paper: Azat O. Tipeev, José P. Rino and Edgar D. Zanotto.
The authors of the paper: Azat O. Tipeev, José P. Rino and Edgar D. Zanotto.

The dilemma aroused so much interest in Zanotto that he set out to investigate whether crystallization of supercooled liquids would occur in less time than structural relaxation. However, this was not an easy task (which is why the paradox persists) and required the mastery of specific computational tools. Thus, the work only started three decades later, when two post-doctoral students specializing in molecular dynamics simulation, Azat Tipeev and Leila Separdar, joined Professor Zanotto’s research group. The new members received co-orientation from Professor José Pedro Rino, also a specialist in the technique, who is a colleague of Zanotto at UFSCar and at the Center for Research, Technology and Education in Vitreous Materials (CeRTEV). While Azat was focusing over liquid germanium, Leila was working on the same problem with other substances. Some of the results of Leila’s work are published in this article in the journal Computational Materials Science.

“Molecular dynamics simulations allow the study of crystallization and relaxation at the atomistic level, in a region of states not yet attainable by laboratory experiments, to obtain essential information about the properties of tiny crystal nuclei in an extremely short time scale and, consequently, testing nucleation and relaxation theories,” explains post-doc Azat, of Russian nationality, who met Professor Zanotto in 2012 at an event on crystallization of glass and liquids in Germany and came for the first time to Brazil in 2015 to participate in the Advanced School of Glass and Vitroceramics organized by Zanotto with funding from FAPESP.

Based on the simulations, the authors determined the structural relaxation and stresses times and compared them with the formation times of the first crystal nucleus at different temperatures. “We found that these curves intersected at the so-called kinetic spinodal temperature, establishing a temperature region where the (strong) interference of relaxation in nucleation must be considered by theoretical models to adequately describe the dynamics of experimental nucleation,” summarize the authors.

- Left, 2D representation of the initial and final configuration of the studied system: super-cooled liquid germanium containing an inserted crystal seed and fully crystallized liquid. Right, characteristic times in supercooled liquid germanium. Blue curve: structural relaxation time. Red curves: average time to formation of the first critical crystal core for different volumes of supercooled liquid. Vertical lines: glass transition temperature, spinodal kinetic temperature and Kauzmann temperature.
Left, 2D representation of the initial and final configuration of the studied system: super-cooled liquid germanium containing an inserted crystal seed and fully crystallized liquid. Right, characteristic times in supercooled liquid germanium. Blue curve: structural relaxation time. Red curves: average time to formation of the first critical crystal core for different volumes of supercooled liquid. Vertical lines: glass transition temperature, spinodal kinetic temperature and Kauzmann temperature.

Furthermore, the work provided solid evidence for the resolution of the Kauzmann paradox. “Our work demonstrated that the supercooled germanium liquid crystallizes before reaching the Kauzmann temperature, avoiding the entropy catastrophe,” says Azat, who is the first author of the article reporting this research in the journal Acta Materialia.

The new articles co-authored by Azat, Leila and Pedro Rino are part of the vast scientific production that Professor Zanotto and his collaborators have in the area of glass materials. “The crossing of relaxation and nucleation times above the Kauzmann temperature is significantly important to clarify the processes and dynamics of vitrification and crystallization and the very nature of the glassy state,” says Zanotto.

The work was carried out with funding from FAPESP.


Scientific paper reference: Unveiling relaxation and crystal nucleation interplay in supercooled germanium liquid. Azat O. Tipeev, José P. Rino, Edgar D. Zanotto. Acta Materialia. Volume 220, November 2021, 117303. https://doi.org/10.1016/j.actamat.2021.117303.

Author contact: Edgar Dutra Zanotto – dedz@ufscar.br

B-MRS Newsletter. Year 8, issue 9.


 

 

20Anos_260px

Newsletter of the
Brazilian Materials
Research Society

Year 8, issue 9. November 8, 2021.

B-MRS elections

– The electoral commission received the registration of a candidate slate for the Executive Board of B-MRS. Find out who the members of the slate are here.

– Registration of members who would like to be part of the Deliberative Council remains open until November 15th. Contact by email eleicoes2021@sbpmat.org.br

– Learn more about the B-MRS 2021 electoral process here.

– Meet the members of the electoral commission that is conducting the process here.

Featured paper

Researchers from Pernambuco institutions report a simple and clean method to synthesize composites of nanotubes and quantum dots that can be used as photoanodes to produce hydrogen from water molecules and sunlight. The article was published in the Journal of Power Sources. Know more.

artigo destaque news

Papers suggested by the community

Researchers from UNESP, together with collaborators from Germany and the USA, studied the free radicals of melanin, a pigment that has aroused great interest due to its possible applications in bioelectronic devices. They used a magnetic field almost 30 times greater than that found in the literature to increase the sensitivity of the EPR technique and thus be able to distinguish free radical species. Access the paper here.

Student Awards 2021

We invited the winners of the XIX B-MRS Meeting + IUMRS ICEM student awards (B-MRS, ACS and RSC awards) to talk about the awarded works, briefly and in an uncomplicated way. See on B-MRS’s YouTube.

students awards

XX B-MRS Meeting

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In response to requests from the community, the organizing committee of the XX B-MRS Meeting extended the deadline for submitting the symposium proposals.
The event will be held in Foz do Iguaçu from 25 to 29 September, 2022. The chairladies are professors Lucimara Stolz Roman (UFPR) and Marcela Mohallen Oliveira (UTFPR).

New deadline for submission of symposium proposals: November 15th.

Event website: https://www.sbpmat.org.br/20encontro/

Opportunities

– Open until December 31, the nominations for the Soft Matter Lectureship, an award promoted by journals of the Royal Society of Chemistry for researchers in the beginning of their careers with outstanding contributions in the field of soft matter. Know more.

– Sirius, the new Brazilian synchrotron light source, accepts proposals for commissioning experiments in several experimental stations. Know more.

News from B-MRS members

Prof. Mariana Amorim Fraga (Mackenzie) is the editor, together with other researchers from the United States and Turkey, of a book published by Elsevier on challenges for the efficient use of solar energy. Know more.

socia mariana

Reading tips

– In 2D materials, electrons can freeze into arrays called Wigner crystals, which were predicted 90 years ago. Now scientists have managed to make the first image of a Wigner crystal, using a graphene trap and a tunneling microscope (Nature). Know more.

– Based on biomaterial, new vaccine against Covid-19, which has been successfully tested in mice, “recruits” immune system cells in the injection area and generates adaptive immunity (Advanced Healthcare Materials). Know more.

– Video: Webinar by Prof Ado Jorio (UFMG) about the Brazilian nanoscope – the science, technology and innovation that were necessary to develop the instrument and carry out the experiments that featured a cover of Nature. Watch the video on YouTube channel of UC Materials Catalão, one of the University Chapters of B-MRS.

Events

– 5th International Conference on Applied Surface Science. Palma, Mallorca (Spain). April 25 – 28, 2022. Site.

– 4th Workshop on Coated Tools & Multifunctional Thin Films. Campinas, SP (Brazil). 20 a 23 de julho de 2022. Site.

– XVIII International Small Angle Scattering Conference. Campinas, SP (Brazil). 11 a 16 setembro de 2022. Site.

– 11th International Conference of the African Materials Research Society (AMRS2022 ). Dakar (Senegal). 12 a 15 de dezembro de 2022. Site.

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