Dr Heloisa Nunes Bordallo uses neutrons and other complementary techniques to study a range of materials that are relevant to our daily lives including dental cements, food, drug molecules and hair bleach. The common theme that runs through these examples is the presence of water confined in porous polymer frameworks. She uses a range of spectroscopy techniques to study the dynamics of hydrogen bonding in these frameworks, and how the polymers that are held together by these bonds change under different conditions.
In a dental cement, a glassy component is mixed with an aqueous solution, forming a mixture in which strong hydrogen bonds form. Using Quasielastic Neutron Scattering (QENS) on the IRIS instrument at ISIS, Dr Bordallo was able to study the hydrogen bonding network as it formed. To study faster reactions, down to the femtosecond timescale, she uses the TOSCA beamline. Combining the results from experiments on different spectrometers, she can study how a framework behaves over a large range of timescales.
Another feature of TOSCA that Dr Bordallo has used is the ability to do simultaneous Raman spectroscopy. She applied this during a study of psychotic drugs, which meant she was able to define more clearly the peaks caused by the vibrations in the complex drug molecules. This knowledge of the way the individual drug molecules move could be used in the future by those developing new medicines.
By using complex sample environments, her group studies porous polymers in the presence of different gases. This includes the investigation of a material that can capture the toxic gas ammonia from the atmosphere, with potential applications in face masks. By combining neutron spectroscopy experiments with DFT calculations using the STFC computing clusters, she was able to determine exactly how the ammonia was binding to the polymer framework. This understanding will inform the design of future materials with tuneable functionality.
As well as progressing her own research, Dr Bordallo has also introduced many students to the benefits of neutron scattering. These students then take their knowledge of neutrons with them into academia, industry, or teaching.
She is a vocal advocate of using neutrons and continues to raise awareness of the uniqueness of neutron spectroscopy to communities that would otherwise not use the technique, such as cosmetic scientists, dental researchers and, more recently, food scientists.
Related publications:
C.R.R. de Castro Lima, R.J.S. Lima, L.D.B. Machado, M.V.R. Velasco, L. Lakic, M.S. Nordentoft, L. Machuca-Beier, S. Rudić, M.T.F. Telling, V. Garcia-Sakai, C.L.P. de Oliveira, H.N. Bordallo (2020) Human hair: subtle change in the thioester groups dynamics observed by combining neutron scattering, X-ray diffraction and thermal analysis. Eur. Phys. J. Special Topics 229, 2825-2832.
R. J. S. Lima, D. V. Okhrimenko, S. Rudić, M. T. F. Telling, V. Garcia Sakai, D. Hwang, G. N Barin, J. Eckert, J-W.Lee, and H. N. Bordallo (2020) Ammonia Storage in Hydrogen Bond-Rich Microporous Polymers. ACS Appl. Mater. Interfaces 12, 58161–58169
