in2science #5

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Press Release

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong.

Press Release: New publication: Successful Mechanical Testing of Nanowires

Insitute of Materials Research

The department:
Hybrid Materialsystems


The gold expert: Nadiia Mameka

About high-performance materials and love of her motherland

Poto: HZG/Nadiia Mameka; HZG/Gesa Seidel

Photo: HZG/Nadiia Mameka; HZG/Gesa Seidel

Dr. Nadiia Mameka is conducting research in the field of hybrid material systems at the Institute of Materials Research

Born in Ukraine, this scientist had never planned to move abroad – today she is glad that she took that step: Nadiia Mameka completed her bachelor’s and master’s degree in physics in Kiev. Motivated by the positive experiences of her friends and colleagues, she applied for a scholarship in Germany. Her stay at the Ruhr-University Bochum changed her life: “Since then I knew that I wanted to do my doctoral studies in Germany. Here, scientists have excellent research opportunities. Unfortunately, in my home country, the prospects for young scientists are currently limited.” It was for this reason that Nadiia Mameka moved to Grünhof-Tesperhude and started her doctoral thesis at the HZG, in the Institute of Materials Research.

“I am excited about how freely and independently research can be conducted in Germany.”

In the "Hybrid Material Systems" group, the scientists investigate phenomena that act on surfaces to better understand their properties. One of the research objectives is to develop intelligent materials with unique functional properties through controllable surface modification.“ We use nanoporous metals, as they posses an extremely large internal surface area: For instance, one gram of nanoporous gold has an internal surface area of more than ten square metres!” Nanoporous gold was the subject of Mameka’s PhD. She studied how the metal’s surface state can be changed electrochemically and through an electric voltage, and what effect this has on the mechanical properties.“ It is a kind of metal muscle: The metal can change its length, for example, through electrical signals. This process is even reversible; this means that we can completely control the material’s behaviour,” she says, her eyes gleaming. “In one experiment, we observed up to about ten percent change in the stiffness of the material. And that is without structural changes, only by variations of the surface state,” explains the materials scientist, who earned a doctorate in 2015. Currently, it is still fundamental research, but at some point, these structures can be integrated as sensor elements in various devices.

“Luckily, I was off ered a post-doctorate position at the HZG – when I saw the results of my research, I really wanted to continue working on the subject,” says Mameka. “It is an indescribable feeling to observe something that no one has seen before and that no one yet understands. At first, it seems like magic, although we know that there must be logic behind it. It really motivates me. The next step consists of developing new approaches towards surface modification in these materials. For example, right now we are working on combining the nanoporous metals with electrically conductive polymers to discover new functions.”

Her next main goal is to propose her own research project. She was particularly inspired by the 2017 Nobel Laureate Meeting in Lindau, in which she participated as a young scientist. There young researchers meet renowned scientists, Nobel Prize winners. “People from different countries and cultures took part – it was a great honour for me to have been selected among the many applicants all over the word. It shows that our research has been recognised in the scientific community.” Through discussions with leading as well as emerging researchers, she learned a simple but important truth:

“A key to success is to love what you do and work hard for it. They told me I should fi ght for my dream, and that is what I will do.”

As well as all the work, experiments, conferences and publications, there is also a counterweight for her; work-life-balance is not just a theoretical construct for Nadiia Mameka. She especially needs a physical counterweight; she likes hiking, cycling and going to the fi tness studio. “When I am surrounded by nature, I can switch off properly” – that was the main reason for living in Geesthacht Grünhof instead of moving to Hamburg.

Through the international environment in which she researches, the physicist has become acquainted with many cultures over the years and built many friendships. She likes travelling and enjoys cooking and baking, especially Ukrainian dishes. Her favourite dish is borscht, the well-known soup with meat, beetroot and other vegetables.

“Baking is a bit like materials science – mixing various ingredients together and achieving a completely different product at the end.”

The 31-year-old hopes that her home country, Ukraine, will overcome its political and economic problems: “Then we could return and give back to the country what we have received. Later, I would like to teach at a university and pass on my knowledge and encourage young people. Investing in one’s own country is the best one can do.”

Author: Gesa Seidel
Portrait from in2science #5 (December 2017)